ātmany eva vaśaṁ nayet

yatah-whatever; yatah-wherever; niscalati-verily agitated; manah-the mind; cancalam-flickering; asthiram-unsteady; tatah-from there; tatah-and thereafter; niyamya-regulating; etat-this; atmani-in the self; eva-certainly; vasam-control; nayet-must bring in.