‘And so it was at that time that Abimelech, and Phicol the captain of his host, spoke to Abraham saying, “God is with you in all that you do. Now therefore swear to me here by God that you will not deal falsely with me, nor with my son, nor with my son's son. But in accordance with the kindness that I have done to you, you shall do to me and to the land wherein you have sojourned ”.'
While it is clear that this has in mind Abraham's reputation as a ‘prophet', who thus has extraordinary powers and influence with the divine, gained in Genesis 20, it would not have arisen unless Abraham's family tribe with its private army had been seen as a real threat (Genesis 21:23), and that clearly indicates that the ‘host' over which Phicol is captain is not all that large. They are not speaking as a powerful nation but as a fair sized but vulnerable group (compare Genesis 26:16).
The names Abimelech and Phicol occur again in Genesis 26 (see especially Genesis 26:26). This may be because young men have grown old, or because the names Abimelech and Phicol were titles assumed by the leader and military captain of the group. We can compare the Egyptian title ‘Pharaoh' which was used as a name and how ‘Tartan' was the name applied to Assyrian generals (2 Kings 18:17; Isaiah 20:1) - as we know from inscriptions.
Abimelech is a Semitic name meaning ‘Melech (or ‘the divine king' - later known as Molech to the Israelites because the vowels were changed to indicate abomination) is my father'. It is used of Achish, the Philistine king of Gath, in the superscription to Psalms 34, demonstrating its connection with the Philistines. It would be prudent for the leader of foreign traders to have a Semitic sounding name. Phicol is of unknown provenance.
“God is with you in all that you do”. Abraham's local reputation as a prophet has never been forgotten. The group are somewhat afraid of his divine connections.
“Now therefore swear to me here by God --”. The specific aim of the approach is a treaty, confirming the previous treaty and expanding it. In return for certain rights yet to be agreed the tribe were to swear friendship with Abimelech and his people. ‘The kindness that I have shown to you' covers some of those rights.