Albert Barnes Commentary Deuteronomy 23:15-16

"Thou shalt not deliver unto his master a servant that is escaped from his master unto thee: he shall dwell with thee, in the midst of thee, in the place which he shall choose within one of thy gates, where it pleaseth him best: thou shalt not oppress him." — Deuteronomy 23:15-16 (ASV)

The case in question is that of a slave who fled from a pagan master to the holy land. It is of course assumed that the refugee was not fleeing from justice, but only from the tyranny of his lord.