“The river of Egypt” occurs seven times in the Authorised Version, but two distinct Hebrew words are used. In Genesis 15:18 and 2 Kings 24:7 the Hebrew word is nahar—a stream or river. The word is used to describe a large river (cp Gen 2:10,13,14; 2 Kings 5:12), hence in Exodus 7:19 Aaron stretched his rod “upon the waters of Egypt, upon their streams (nahar), upon their rivers and upon their ponds”.

When Nebuchadnezzar was given the land of Egypt as a reward for taking Tyre, 2 Kings 24:7 informs us that he “had taken from the river of Egypt (nahar) unto the river Euphrates all that pertained to the king of Egypt”. This is a reference to the Nile which was the lifeblood of Egyptian political power.

Hence when God promised Abraham the land from the river (nahar) of Egypt he was setting the Nile as its southern boundary, even though the Hebrew word for Nile was not used.

The other Hebrew word used to describe “the river of Egypt” occurs in Numbers 34:5; Joshua 15:4,47; 1 Kings 8:65 and 2 Chronicles 7:8. This is the word nahal, which refers to a winter torrent. This is most likely the modern-day Wadi El-Arish which is just south of the current Israel-Egyptian border. This was the general southern limit of the kingdom of Judah in the days of the monarchy—from Dan to Beersheba.

It would appear that God limited the extent of that kingdom to that winter torrent because He was asking the nation to look in faith beyond their current circumstances to the fullness of the promises made to the fathers when He would give the faithful all the land from Egypt to Syria.