“ YHWH recompense your work, and a full reward be given you by YHWH, the God of Israel, under whose wings you are come to take refuge.”
Boaz's godliness comes out in his wish for Ruth, that she be recompensed by YHWH, the God of Israel, and given the full reward that she deserved. In view of his age he was probably unaware at this moment that he would prove the answer to his own prayer.
Especially important in the narrative are his words concerning the fact that she had come ‘to take refuge under the wings of YHWH'. This would suggest that he was aware of her piety and genuine love for YHWH. To take refuge under the wings of YHWH indicated a commitment to the covenant. But what is even more important is that it was making clear to the reader or listener that her faith in YHWH was true and genuine. She was a genuine proselyte and as such one of the children of Israel by adoption (Exodus 12:48). What follows in the story would not have happened had it been otherwise. While her race would not matter (it was deemed more important with males), especially because she had married an Israelite, her attitude towards YHWH and His covenant would matte. It is this continued emphasis that indicates that part of the reason for the account was in order to indicate to would be proselytes that they could be totally accepted into Israel. This was especially important at the time of David's greatness when many foreigners would have been considering the claims of YHWH.
This figurative expression is derived from Deuteronomy 32:11, and we can compare Psalms 91:4; Psalms 36:7; Psalms 57:1. It was a classic description of someone who was genuinely true to the covenant and therefore under the protection of YHWH.