Genesis 20:7

"Now therefore restore the man's wife; for he is a prophet, and he shall pray for thee, and thou shalt live: and if thou restore her not, know thou that thou shalt die, thou, and all that are thine."

"For he is a prophet ..." "This is the first time that the word prophet appears in the Scripture,"[8] and we are unwilling to assign any lesser meaning of this term here than the meaning usually understood in the term throughout the Bible. The critical allegation that "prophet" was a term that did not appear until the times of Samuel is ridiculous in the light of what is revealed here. God Himself used the term in a revelation to Abimelech long centuries before Samuel ever lived. There was a period during which the word prophet seems to have fallen into disuse, and it was revived in the times of Samuel.[9] Of course, the radical critical scholars would like to prove that none of the Pentateuch existed before the times of Samuel, but such views should be rejected as sheer nonsense.

Whitelaw listed the function of a prophet as being (1) that of announcing the will of God to men, and (2) that of interceding with God on behalf of men.[10] Not only did Abraham exercise the office of prophet in the intercessory prayer for Sodom, but he also did the same here in his intercession with God on behalf of Abimelech and his household. The record also states that he would "command his children after him" (Genesis 18:19), which he could not have done without communicating the will of God to his posterity. Dummelow summed up Abraham's status as truly a prophet in these words: "A prophet is one to whom God reveals his will, and who in turn declares it to men; and thus one who can mediate between God and man, as in this case (the case of Abraham)."[11]