Sri Krishna in this verse ask Arjuna to fix his mind in him .Further he ask that the Intellect also should be also set to Sri Krishna . Once this is done , one can live in him .
Sri Krishna is a representation of the higher ideal of self . However , as the higher ideal of self , is itself having no form , so it would be very hard to focus on higher ideal. So, Sri Krishna gives an easy route to Arjuna . As Sri Krishna, already have his mind, towards higher ideal, and the Intellect towards awareness , if somebody focuses on his form, and fix him in his mind and intellect , he could gain the similar experience .