tasmat sarvesu kalesu
mam snusmara yudhyaca
mayy arpita mano-buddhir
mam evaisyasy asamsayah
Translation: Therefore, Arjuna, you should always think of Me in the form of Krsna 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.
PURPORT by A.C Bhaktivedanta Swami 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 Krsna by chanting Hare Kṛṣṇa. This will free one from material contamination and engage the mind and intelligence in Krsna. By chanting Krsna's names, one will be transferred to the supreme planet, Kṛṣṇaloka, without a doubt.
(Bhagavad Gita As It Is Text 6, Chapter 8)