SB 11.13.13
apramatto ’nuyuñjita
mano mayy arpayañ chanaih
anirvinno yatha-kalam
jita-svaso jitasanah
Translation:
A person should be attentive and grave and never lazy or morose. Mastering the yoga procedures of breathing and sitting properly, one should practice fixing the mind on Me at dawn, noon and sunset, and thus gradually the mind should be completely absorbed in Me.