* Sarah.
  21  18:10-14  21:2,3,6  2Ki 4:16,17  Lu 1:13-20  Ro 9:6-9  Ga 4:28-31 
 * Isaac.
   {Yitzchak,} which we change into Isaac, signifies laughter; in
   allusion to Abraham's laughing, ver. 17.  By this Abraham did
   not express his unbelief or weakness of faith, but his joy at
   the prospect of the fulfilment of so glorious a promise; and
   to this our Lord evidently alludes, Joh 8:56.