‘And see, the word of Yahweh came to him saying, “This man will not be your heir. He who will be truly of your own blood (will come forth out of your own bowels) will be your heir”.'
We note that the writer himself responds to Abram. He responds to Abram's ‘see' (‘behold'), twice repeated, with a third ‘see' (‘behold'). Three is the number of completeness and he wants us to know that what Abram was calling God to look at is completely answered.
“The word of Yahweh came to him”. He has become a prophet and his first prophecy will be concerning his own deepest desires. ‘This man will not be your heir, one who is of your own body and blood will be your heir.' This is what he had craved, and this Yahweh gives him. A child of his own.
And yet it had not been a totally selfish craving, it had been a craving that God would fulfil in him what He had commanded in all, ‘Be fruitful and multiply' (Genesis 1:28; Genesis 9:1; Genesis 9:7). He had not only felt sick at heart, he had felt that he had failed God. But now Yahweh Himself assures him that this will not be so. He is to have a son and heir.