Jamieson, Fausset and Brown on 1 Chronicles 2:35

35. Sheshan gave his daughter to Jarha his servant to wife--The adoption and marriage of a foreign slave in the family where he is serving, is far from being a rare or extraordinary occurrence in Eastern countries. It is thought, however, by some to have been a connection not sanctioned by the law of Moses [Michaelis]. But this is not a well-founded objection, as the history of the Jews furnishes not a few examples of foreign proselytes in the same manner obtaining an inheritance in Israel; and doubtless Jarha had previously embraced the Jewish faith in place of the grovelling idolatries of his native Egypt. In such a case, therefore, there could be no legal difficulty. Being a foreign slave, he had no inheritance in a different tribe to injure by this connection; while his marriage with Sheshan's daughter led to his adoption into the tribe of Judah, as well as his becoming heir of the family property.