The Bhagavad Gita with Commentaries of Ramanuja, Madhva, Shankara and Others.
Bhagavad Gita 8.7
http://www.bhagavad-gita.us/articles/359/1/Bhagavad-Gita-87/Page1.html
By Bhagavan Sri Krishna
 

Text 7

tasmat sarveshu kaleshu
mam anusmara yudhya ca
mayy arpita-mano-buddhir
mam evaishyasy asamsayah

Translation

Therefore, Arjuna, you should always think of Me in the form of Krishna and at the same time carry out your prescribed duty of fighting. With your activities dedicated to Me and your mind and intelligence fixed on Me, you will attain Me without doubt.

Commentary by Srila Prabhupada

This instruction to Arjuna is very important for all men engaged in material activities. The Lord does not say that one should give up his prescribed duties or engagements. One can continue them and at the same time think of Krishna by chanting Hare Krishna. This will free one from material contamination and engage the mind and intelligence in Krishna. By chanting Krishna’s names, one will be transferred to the supreme planet, Krishnaloka, without a doubt.

Commentary by Sri Visvanatha Cakravarti Thakur

The mind creates the decision to think of me. The intelligence creates the determination to do so.