Or HaChaim on Leviticus 25:55/אור החיים על ויקרא כ״ה:נ״ה

1 כי לי בני ישראל עבדים, "For the children of Israel are My servants, etc." Why did the Torah write once more עבדי הם, "they are My servants?" Perhaps the point G'd makes here is that "they are My servants" as they are of sacred origin, their souls and their bodies are intrinsically holy independent of the Exodus from Egypt. The factor which obligates the Israelites to conduct themselves in a manner befitting holy creatures is "that I took them out of the land of Egypt." Ever since, G'd says, they themselves realise that they are My servants.

2אני ה׳ אלוקיכם, "I am the Lord your G'd." Why did the verse commence in the third person, i.e. G'd speaking about the Israelites, whereas it concludes with direct speech, i.e. "I am the Lord your G'd?" Perhaps we have to look for the reason in the laws governing the sale and purchase of a slave. We have the law that if someone acquires a Jewish servant he has to free him in the Jubilee year. G'd therefore had to state that the Jew remains His servant also in the Jubilee year and beyond, i.e. עבדי הם. The purchaser of the Jewish servant may argue that this fact is justification for a Jew not being allowed to sell himself into permanent servitude, but this fact does not impose an obligation on the purchaser. If the Jew had sold himself to a resident stranger, גר תושב, that resident stranger would argue that he had no oligation to release the servant merely because of the Jubilee year. G'd therefore states categorically: "I am the Lord your G'd," i.e. I address you the purchaser the very person whom the Torah addressed at the beginning of this paragraph in verse 39 and subsequently in verse 44 when it spoke about ונמכר לך, "and he was sold to you." The Torah wanted to be sure the owner understood that he was expected to comply with the entire legislation recorded here.