Luther

Thus you may read in the book of the Elders, that a young brother wanted to get rid of his thoughts. Said the Elder, Dear brother, you cannot hinder the birds in the air from flying over your head; but you can prevent them from building a nest in your hair. In that self-same manner (as St. Augustine says) we cannot guard ourselves against temptation and stumbling; but with prayer and with the help of God we can prevent them from overcoming us.—Exposition of the Lord’s Prayer for Simple Lay-folk