Question: Deuteronomy 23:15-16. verse 15: Thou shalt not deliver unto his master the servant which is escaped from his master unto thee: verse:16 He shall dwell with thee, even among you, in that place which he shall choose in one of thy gates, where it liketh him best: thou shalt not oppress him. I have argued that this passage means that if a slave (or bondservant) escapes his master that he shouldnt be returned to the original master. A person in our group has stated that this passage refers to “slave sitting”. That is, that the verses above refer to servants that are handed over from one master to another for safe keeping. When these texts are examined in the original Hebrew, what is the truest meaning as far as any of you know?

Answer: For your interest I am giving you an interpretation that ties this law to the one above about the sanctity of the army. From the Stone Chumash:

During a siege of an enemy city, it is common for slaves and prisoners to try and escape to the “liberators.” The Torah commands Israel that such escapees must be given their freedom and permitted to settle wherever they wish in the Land of Israel. In the moral sense, for the nation that maintains the holiness of its camp—as required by the above passage—to send a man seeking his freedom back to a life of idolatry would be most unseemly. In the practical sense, people seeking asylum often become important allies of the invaders, because they reveal valuable information that will help in the conquest.
(Ramban)