1;  The Lord appears to Abraham, who entertains angels.
  9;  Sarah is reproved for laughing at the promise of a son.
 16;  The destruction of Sodom is revealed to Abraham.
 23;  Abraham makes intercession for the inhabitants.
 
 * appeared.
  15:1  17:1-3,22  26:2  48:3  Ex 4:1  2Ch 1:7  Ac 7:2 
 * Mamre.
  13:18  14:13 
 * and he sat.
   In these verses we have a delightful picture of genuine and
   primitive hospitality:  a venerable father sits at the tent
   door, not only to enjoy the current of refreshing air, but
   that if he saw any weary and exhausted travellers, he might
   invite them to rest and refresh themselves during the heat of
   the day, and the same custom still continues in the east.  It
   was not the custom, nor was there any necessity, for strangers
   to knock at the door, or to speak first, but to stand till
   they were invited.