Bg 12.2

sri-bhagavan uvaca
mayy avesya mano ye mam
nitya-yukta upasate
sraddhaya parayopetas
te me yukta-tama matah

Word for word: 
sri-bhagavan uvaca — the Supreme Personality of Godhead said; mayi — upon Me; avesya — fixing; manah — the mind; ye — those who; mam — Me; nitya — always; yuktah — engaged; upasate — worship; sraddhaya — with faith; paraya — transcendental; upetah — endowed; te — they; me — by Me; yukta-tamah — most perfect in yoga; matah — are considered.

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The Supreme Personality of Godhead said: Those who fix their minds on My personal form and are always engaged in worshiping Me with great and transcendental faith are considered by Me to be most perfect.

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In answer to Arjuna’s question, Krishna clearly says that he who concentrates upon His personal form and who worships Him with faith and devotion is to be considered most perfect in yoga. For one in such Krishna consciousness there are no material activities, because everything is done for Krishna. A pure devotee is constantly engaged. Sometimes he chants, sometimes he hears or reads books about Krishna, or sometimes he cooks prasadam or goes to the marketplace to purchase something for Krishna, or sometimes he washes the temple or the dishes – whatever he does, he does not let a single moment pass without devoting his activities to Krishna. Such action is in full samadhi.