Charles Ellicott Commentary Genesis 15:1

"After these things the word of Jehovah came unto Abram in a vision, saying, Fear not, Abram: I am thy shield, [and] thy exceeding great reward." — Genesis 15:1 (ASV)

After these things. — After the war with Chedorlaomer.

The word of the Lord came to Abram. (Hebrew, was) — This phrase, used so frequently afterwards to signify revelation, occurs here for the first time. The revelation on this occasion was made by night (Genesis 15:5), not in a dream, however, but in a trance, during which Abram's senses were closed to all earthly impressions and he became passive in the hands of the Almighty.

Until this time, Abram had received only general promises of offspring and of the land being the possession of his seed; but years were passing by, and the fulfilment of his hopes remained as distant as ever.

By the war with the Elamite king, Abram had also made powerful enemies for himself; and though the immediate result was fortunate, yet many Canaanite nations may have witnessed with displeasure so remarkable an exhibition of the power and energy of an “immigrant.”

And so, the time had come when the patriarch needed and obtained more formal assurances: first, of the bestowal of offspring on him (Genesis 15:1–6), and second, of the future possession of Palestine (Genesis 15:18–21).