And Abram said to the king of Sodom, I have lift up mine hand, etc. This ancient ceremony was very appropriate to give expression to the force and nature of an oath. For by raising the hand towards heaven, we show that we appeal to God as a witness, and also as an avenger, if we fail to keep our oath. Formerly, indeed, they raised their hands in giving votes; whence the Greeks derive the word (cheirotonein,) [1] which signifies to decree: but in the rite of swearing, the reason for doing so was different. For men hereby declared, that they regarded themselves as in the presence of God, and called upon him to be both the Guardian of truth, and the Avenger of perjury. Yet it may seem strange that Abram should so easily have put himself forward to swear; for he knew that a degree of reverence was due to the name of God, which should constrain us to use it but sparingly, and only from necessity. I answer, there were two reasons for his swearing. First, since inconstant men are wont to measure others by their own standard, they seldom place confidence in bare assertions. The king of Sodom, therefore, would have thought that Abram did not seriously remit his right, unless the name of God had been interposed. And, secondly, it was of great consequence, to make it manifest to all, that he had not carried on a mercenary war. The histories of all times sufficiently declare, that even they who have had just causes of war have, nevertheless, been invited to it by the thirst of private gain. And as men are acute in devising pretexts, they are never at a loss to find plausible reasons for war, even though covetousness may be their only real stimulant. Therefore, unless Abram had resolutely refused the spoils of war, the rumor would immediately have spread, that, under the pretense of rescuing his nephew, he had been intent upon grasping the prey. Against which it was necessary for him carefully to guard, not so much for his own sakes as for the glory of God, which would otherwise have received some mark of disparagement. Besides, Abram wished to arm himself with the name of God, as with a shield, against all the allurements of avarice. For the king of Sodom would not have desisted from tempting his mind by various methods, if the occasion for using bland insinuations had not been promptly cut off.

Footnotes

1 - Literally, to stretch forth the hand.

I have lifted up my hand. - This is a serious matter with Abram. Either before, or then and there, he made an oath or solemn asseveration before God, with uplifted hand, that he would not touch the property of Sodom. He must have felt that there was danger of moral contamination in coming into any political relationship with the cities of the vale. "The Lord, the Most High God, the Founder of heaven and earth." In this conjunction of names Abram solemnly and expressly identifies the God of himself and of Melkizedec in the presence of the king of Sodom. The Most High God of Melkizedec is the God of the first chapter of Genesis, and the Yahweh of Adam, Noah, and Abram.

I have lift up mine hand - The primitive mode of appealing to God, and calling him to witness a particular transaction; this no doubt generally obtained among the faithful till circumcision, the sign of the covenant, was established. After this, in swearing, the hand was often placed on the circumcised part; see Genesis 24:2, Genesis 24:9.

And Abram said to the king of Sodom,.... In reply to his request:
I have lifted up mine hand unto the Lord; which was both a gesture of praying and of swearing, and both may be intended here; when he set out on his expedition, it is very probable he prayed to God for success, and swore that if he prospered him, that he would receive no profit or advantage from it to himself; or now in the presence of Melchizedek he lift up his hands and swore that he would take none of the goods he had recovered to his own line; and in this form of praying or swearing, he makes use of the same epithets of God Melchizedek had just used:
the most high God, the possessor of heaven and earth: having his heart struck with those just and glorious representations of God, and awed with a sense of such a glorious Being, and being forward to learn and retain everything that tended to make for the glory of God.

I have lift up mine hand to the Lord that I will not take anything - Here Observe, The titles he gives to God, the most high God, the possessor of heaven and earth - The same that Melchizedek had just now used. It is good to learn of others how to order our speech concerning God, and to imitate those who speak well in divine things. The ceremony used in this oath; I have lift up my hand - In religious swearing we appeal to God's knowledge of our truth and sincerity, and imprecate his wrath if we swear falsely; and the lifting up of the hands is expressive of both. Lest thou shouldst say, I have made Abram rich - Probably, Abram knew the king of Sodom to be a proud and scornful man, and one that would be apt to turn such a thing as this to his reproach afterwards, and when we have to do with such men, we have need to act with particular caution.