When the breath wanders the mind also is unsteady. But when the breath is calmed the mind too will be still, and the yogi achieves long life. Therefore, one should learn to control the breath. Svatmarama, Hatha Yoga Pradipika

Anyone who practices can obtain success in yoga but not one who is lazy. Constant practice alone is the secret of success. Svatmarama, Hatha Yoga Pradipika