And the Lord—Jehovah, the Divine name employed throughout the present and succeeding chapters, which are accordingly assigned to the Jehovist (Tuch, Bleek, Davidson, Colenso), with the exception of Genesis 19:29, which is commonly regarded as a fragment of the original Elohist's narration (vide infra)—appeared unto him.
The absence of Abraham's name has been thought to favor the idea that the present chapter should have begun at Genesis 17:23 (Quarry). That the time of this renewed Divine manifestation was shortly after the incidents recorded in the preceding chapter is apparent, as also that its object was the reassurance of the patriarch concerning the birth of Isaac.
In the plains of Mamre. Literally, in the oaks of Mature (vide Genesis 13:18). And he sat in the tent door. Literally, in the opening of the tent, a fold of which was fastened to a post near by to admit any air that might be stirring.
In the heat of the day, i.e. noontide (cf. 1 Samuel 11:11), as the cool of the day, or the wind of the day (Genesis 3:8), means eventide. "The usual term for noon is Tsoharim (Genesis 43:16), that is, the time of ' double or greatest light,' while a more poetical expression is 'the height of the day' (Proverbs 4:18), either because then the sun has reached its most exalted position, or because it appears to stand still in the zenith" (Kalisch).
Among the Orientals the hour of noon is the time of rest (cf. So Genesis 1:7) and the time of dinner (Genesis 43:16, Genesis 43:25). In this case the patriarch had probably dined and was resting after dinner, sines, on the arrival of his visitors, preparations had to be commenced for their entertainment.