Genesis 28:20

And Jacob vowed a vow — By religious vows we give glory to God, and own our dependance upon him, and we lay a bond upon our own souls, to engage and quicken our obedience to him. Jacob was now in fear and distress, and in times of trouble it is seasonable to make vows, or when we are in pursuit of any special mercy, Jonah 1:16; Psalms 66:13; 1 Samuel 1:11; Numbers 21:1. Jacob had now had a gracious visit from heaven, God had renewed his covenant with him, and the covenant is mutual; when God ratifies his promises to us, it is proper for us to repeat our promises to him. If thou wilt be with me and keep me — We need desire no more to make us easy and happy wherever we are, but to have God's presence with us, and to be under his protection. It is comfortable in a journey to have a guide in an unknown way, a guard in a dangerous way, to be well carried, well provided for, and to have good company in any way; and they that have God with them, have all this in the best manner. Then shall the Lord be my God — Then I will rejoice in him as my God, then I will be the more strongly engaged to abide with him. And this pillar shall be God's house — That is, an altar shall be erected here to the honour of God. And of all that thou shalt give me I will surely give the tenth unto thee — To be spent either upon God's altar or upon his poor, which are both his receivers in the world. The tenth is a very fit proportion to be devoted to God, and employed for him; though as circumstances vary, it may be more or less, as God prospers us.