Genesis 28:20 - Coke's Commentary on the Holy Bible

Jacob vowed a vow, &c.— This is the first time we find mention made of a vow, which was allowed then, and in after-ages, to be a part of religion, and no doubt had been inculcated upon Jacob as such by his pious ancestors. See Psalms 50:14; Psalms 65:1; Psalms 65:13. The plain meaning of Jacob's vow is this: "If God shall be pleased to preserve me, that I may return again to this place, then will I glorify him here in a public and remarkable manner, by adhering stedfastly to the true religion in the midst of this land of idolaters; and this place where I have set up a pillar, will I mark as my most solemn place of public worship, ch. Genesis 35:3. and the tythe of all that I get before my return will I consecrate to God, either by applying it to the maintenance of the poor, or for other pious uses." From which explication it appears that the vow has no particular and immediate reference to that internal worship of God, which is our indispensable duty at all times and in all places, otherwise we might well suppose that Jacob intended to forsake the God of his fathers during the interval; but that it refers only to special acts of gratitude and religion. Jacob's moderation in requesting only the necessaries of life, food and raiment, shews his character in an amiable view.