Self-surrender means: To practice contentment by thinking that wherever the Lord keeps me is for my good; to unify one’s will with the will of God; and to practice even-mindedness in happiness and misery, gain and loss, and so on. In other words, one can surrender oneself completely only after liberation. Before that one will have to practice yoga repeatedly. Real resignation to God is liberation. If a person practices this attitude of resignation sincerely and wholeheartedly, he attains liberation by God’s grace.
(p.67, Spiritual Treasures, Swami Turiyananda’s letter dt 27 September 1913)