The Brahmanas have said that to regulate one's body is the observance of human vows and to purify one's mind and understanding is the observance of celestials vows.
शरीरनियमं प्राहुर्ब्राह्मणा मानुषं व्रतम्। मनोविशुद्धां बुद्धिं च दैवमाहुव्रतं द्विजाः॥