Charles H. Spurgeon on Psalms 65:1

Vow. A vow is a voluntary and deliberate promise made unto God in an extraordinary case. "It is a religious promise made unto God in a holy manner:" so a modern writer defines it. (Szegedinus.) It is a "holy and religious promise, advisedly and freely made unto God, concerning something which to do or to omit appeareth to be grateful and well pleasing unto him:" so Bucanus. I forbear Aquinas's definition of a vow. If these which I have given satisfy not, then view it in the words of Peter Martyr, a man of repute, and well known to our own nation in the days of Edward VI., of ever blessed memory: "It is a holy promise, whereby we bind ourselves to offer somewhat unto God." There is one more who defines it, and he is a man whose judgment, learning, and holiness hath perfumed his name; it is learned Perkins, in his "Cases of Conscience." "A vow, " saith he, "is a promise made unto God of things lawful and possible." Henry Hurst( —1690), in "The Morning Exercises."