mātrā-sparśās tu kaunteya
śītoṣṇa-sukha-duḥkha-dāḥ
āgamāpāyino ‘nityās
tāḿs titikṣasva bhārata

Translation of Bhagavad Gita 2.14

O son of Kunti, the nonpermanent appearance of happiness and distress, and their disappearance in due course, are like the appearance and disappearance of winter and summer seasons. They arise from sense perception, O scion of Bharata, and one must learn to tolerate them without being disturbed.

Commentary by Sri A.C. Bhaktivedanta Swami Prabhupada of Gaudiya Sampradaya:

In the proper discharge of duty, one has to learn to tolerate nonpermanent appearances and disappearances of happiness and distress. According to Vedic injunction, one has to take his bath early in the morning even during the month of Magha (January-February). It is very cold at that time, but in spite of that a man who abides by the religious principles does not hesitate to take his bath. Similarly, a woman does not hesitate to cook in the kitchen in the months of May and June, the hottest part of the summer season. One has to execute his duty in spite of climatic inconveniences. Similarly, to fight is the religious principle of the kshatriyas, and although one has to fight with some friend or relative, one should not deviate from his prescribed duty. One has to follow the prescribed rules and regulations of religious principles in order to rise up to the platform of knowledge, because by knowledge and devotion only can one liberate himself from the clutches of maya (illusion).

The two different names of address given to Arjuna are also significant. To address him as Kaunteya signifies his great blood relations from his mother’s side; and to address him as Bharata signifies his greatness from his father’s side. From both sides he is supposed to have a great heritage. A great heritage brings responsibility in the matter of proper discharge of duties; therefore, he cannot avoid fighting.Commentary by Sri Vishvanatha Chakravarthi Thakur of Gaudiya Sampradaya:

“Yes this is indeed true. I have shown such indiscretion. My mind, producing nonsense, uselessly covered with lamentation and bewilderment, causes me suffering.”

“It is not the one mind alone. The various functions of the mind, in the form of all the senses such as skin, experiencing their sense objects, produce this problem (anartha). One has the experience (sparsa) of the sense object (matra). In the hot season, cold water is pleasant, and in the cold season, it is painful. This happens in an uncontrolled manner, appearing and disappearing (agama apayinah). Therefore you must tolerate these experiences of the sense objects. Tolerating them is part of dharma prescribed in the scriptures. One should not give up the bath in the month of Magha because it gives pain, since it is prescribed in the scriptures. Following dharma gradually rids one of all low qualities. You must tolerate that sons give joy when they are born or earn money, and give sorrow when they die, by their temporary appearance and disappearance. One should not give up one’s scripturally prescribed duty to fight by that consideration. Not performing the prescribed duty eventually brings about great problems.”Commentary by Sri Ramanuja of Sri Sampradaya:

2.14 As sound, touch, form, taste and smell with their bases, are the effects of subtle elements (Tanmatras), they are called Matras. The contact with these through the ear and other senses gives rise to feelings of pleasure and pain, in the form of heat and cold, softness and hardness. The words ‘cold and heat’ illustrate other sensations too. Endure these with courage till you have discharged your duties as prescribed by the scriptures. The brave must endure them patiently, as they ‘come and go’. They are transient. When the Karmas, which cause bondage, are destroyed, this ‘coming and going’ will end. The Lord now explains the purpose of this endurance:Commentary by Sri Sridhara Swami of Rudra Sampradaya:

It may be countered by Arjuna that he was not grieving for those who have died or are living but he was grieving for himself who would be miserable and forlorn by their loss. This is being perfectly answered by the Supreme Lord in this verse. That by which the objects of the senses are preceived is called matra or the functions of the senses which are hearing, seeing, smelling, touching and tasting. Their contact with their appropriate objects produces the sensations of hot and cold, loud and soft, sweet and sour and the like. But as they are solely dependent upon external objects and these objects are always coming and going, they are known to be temporary and thus should be tolerated. Just as contact with the different elements of weather such as snow and sunlight by their very nature give rise to cold and heat. Similarly the contact with the objects of the senses gives rise to pleasure and pain for all living entities and as theses contacts are transitory being temporary one being situated in spiritual knowledge should with fortitude tolerate them and not succumb to lamentation or exaltation because of them.Commentary by Sri Madhvacharya of Brahma Sampradaya:

Even then, in the absence of self-realisation there is always sorrow. therefore it is clarified thus matra means sensuous experience and sparsas means contact with them thus matra-sparsas is the interaction of the senses with sense objects. These interactions are like hot and cold or pleasure and pain. Although only the body is what is actually experiencing these things, anyone with lack of sufficient knowledge who considers that they are their body automatically classifies the soul as the body as well and this misconception is factually the cause of all sorrow.

The experience of sorrow does not affect the individual consciousness by itself. Why is this? Because it appears and disappears. If these contacts of the senses were factually within the individual consciousness then they would also exist in the state of deep sleep. Therefore since it is evident that contact with the senses is experienced only in the waking state and not in any other state; the summation is clear that only when there is contact with the physical body which includes the mind, is there an effect and this proves that the individual consciousness itself is not affected.

Regarding the individual consciousness there is no contact of the sense objects except when it desires a relationship through the experience of senses. Because of their nature of appearing and disappearing like objects floating past on a river, they cannot be classified as eternal due to the fact they cease to exist during deep sleep. Hence they are said to be a- nitya or not eternal.

Consequently when the individual consciousness is deluded into relating to itself as the body, pleasure and pain is experienced; but when the individual consciousness sees itself as separate from the physical body then the sorrow arising from the death of friends and relatives would not arise. Therefore it is by rejection of ones constitutional position as individual consciousness and accepting the position of considering oneself the body that the perception of pleasure, pain, happiness, sorrow and all the rest manifests.

Now begins the summation.

Because of their temporary nature Lord Krishna counsels that reactions arising in the body due to perceptions of the senses should be tolerated as they are temporary. Appearing and disappearing at random with no auspices to the indivdual consciousness.
Commentary by Sri Keshava Kashmiri of Kumara Sampradaya:

Although the delusion of death is not appropriate regarding the misconception of the souls destruction when it is in fact eternal and immortal; still it could be submitted that loss of life would result in great unhappiness when preceptors, friends and relatives are slain in battle departing their physical bodies and from this the delusion that they are dead may arise. To dispel this doubt Lord Krishna replies: that sensory perception or the contact between the senses and their objects give rise to feelings of heat and cold, pleasure and pain. If they are soft and sweet they are pleasing but if they are bitter and harsh they are unpleasant. These things are all temporary, they are not eternal like the soul; but of a fleeting impermanent nature which comes and goes. Therefore one should just tolerate them with discrimination, patience and fortitude for they will disappear in due course of time. By addressing Arjuna as Bharata signifies the great heritage in his ancestry on his fathers side. To address him as Kaunteya signifies the great heritage in his ancestry on his mothers side. This suggests that such delusion is quite improper for Arjuna.
Commentary by Sri Adi Shankaracharya of Advaita Sampradaya:

2.14 ‘In the case of a man who knows that the Self is eternal, although there is no possibility of delusion concerning the destruction of the Self, still delusion, as of ordinary people, caused by the experience of cold, heat, happiness and sorrow is noticed in him. Delusion arises from being deprived of happiness, and sorrow arises from contact with pain etc.’ apprehending this kind of a talk from Arjuna, the Lord said, ‘But the contacts of the organs,’ etc. Matra-sparsah, the contacts of the organs with objects; are sita-usna-sukha-duhkha-dah, producers of cold, heat, happiness and sorrow. Matrah means those by which are marked off (measured up) sounds etc., i.e. the organs of hearing etc. The sparsah, contacts, of the organs with sound etc. are matra-sparsah. Or, sparsah means those which are contacted, i.e. objects, viz sound etc. Matra-sparsah, the organs and objects, are the producers of cold, heat, happiness and sorrow. Cold sometimes produces pleasure, and sometimes pain. Similarly the nature of heat, too, is unpredictable. On the other hand, happiness and sorrow have definite natures since they do not change. Hence they are mentioned separately from cold and heat. Since they, the organs, the contacts, etc., agamapayinah, have a beginning and an end, are by nature subject to origination and destruction; therefore, they are anityah, transient. Hence, titiksasva, bear; tan, them — cold, heart, etc., i.e. do not be happy or sorry with regard to them.
Commentary by Sri Abhinavagupta of Kaula Tantra Sampradaya:    

2.14 Matra etc. But the unwise lament even over those passing situations of cold and heat, pleasure and pain that are created by those touches i.e., the contacts of the sense-objects-referable with the term matra – with the Soul through the door of the sense-organs; but the wise do not do so. Thus says [the Lord]. Or, the passage may be interpreted as : The touches (contacts) of these objects are with the matras, i.e., with the sense-organs, and not directly with the Supreme Self, Coming : birth. Going : destruction, Those situations that have these two you must forbear i.e., put up with.

Sanskrit Shloka Without Transliteration Marks:

matra-sparsas tu kaunteya
sitosna-sukha-duhkha-dah
agamapayino ‘nityas
tams titiksasva bharataSanskrit to English Word for Word Meanings:

mātrā-sparśāḥ — sensory perception; tu — only; kaunteya — O son of Kuntī; śīta — winter; uṣṇa — summer; sukha — happiness; duḥkha — and pain; dāḥ — giving; āgama — appearing; apāyinaḥ — disappearing; anityāḥ — nonpermanent; tān — all of them; titikṣasva — just try to tolerate; bhārata — O descendant of the Bharata dynasty.