For those who are grossly materialistic persons, for them the yogic system is recommended, otherwise if the mind is directly engaged engaged at the lotus feet of Krishna, the senses automatically become engaged in Krishna's service; and that is the liberated stage. Chanting of the Hare Krishna mantra is the direct process for curing the mind of all materialistic contamination. Take to this process and be happy.
Letter to Prem J. Batra, 28 September, 1975