Text 4

sankhya-yogau prithag balah
pravadanti na panditah
ekam apy asthitah samyag
ubhayor vindate phalam

Translation

Only the ignorant speak of devotional service [karma-yoga] as being different from the analytical study of the material world [Sankhya]. Those who are actually learned say that he who applies himself well to one of these paths achieves the results of both. 

Commentary by Srila Prabhupada 

The aim of the analytical study of the material world is to find the soul of existence. The soul of the material world is Vishnu, or the Supersoul. Devotional service to the Lord entails service to the Supersoul. One process is to find the root of the tree, and the other is to water the root. The real student of Sankhya philosophy finds the root of the material world, Vishnu, and then, in perfect knowledge, engages himself in the service of the Lord. Therefore, in essence, there is no difference between the two because the aim of both is Vishnu. Those who do not know the ultimate end say that the purposes of Sankhya and karma-yoga are not the same, but one who is learned knows the unifying aim in these different processes.

Commentary by Sri Visvanatha Cakravarti Thakur

Your statement about which is the better of the two does not actually   apply,   because   intelligent  people do  not  see any difference between the two. The word sankya refers to being fixed in jnana. An anga of that is sannyasa. The fools, not the wise, speak of the difference between sannyasa and karma yoga. As the previous verse mentioned, "one should know the karma yogi to be the real sannyasi." The sannyasi and karma yogi are one.