Sri-bhagavan uvaca
yunjann evam sadatmanam
yogi niyata-manasah
santim nirvana-paramam
mat-samstham adhigacchati
Meaning: Thus practicing constant control of the body, mind and activities, the mystic transcendentalist, his mind regulated, attains to the kingdom of God [or the abode of Krsna] by cessation of material existence.
Bhagavad Gita: Attain kingdom of God (Dhyana-yoga (Text 15 Ch 6))