Leviticus 18:2

Speak with the sons of Israel, and say to them, I am the Lord your God.

I am God your God here means: Only on the following conditions will I be your God.

SPEAK UNTO THE CHILDREN OF ISRAEL. Since this chapter deals with [the laws of] prohibited sexual intercourse which apply equally to all Israel, therefore He said only, Speak unto the children of Israel, and did not specify the priests but included them together. Therefore He said at first, I am the Eternal your G-d, just as He did in the Ten Commandments [which He began with the words, I am the Eternal thy G-d]. And the meaning of the verse, Speak unto the children of Israel, and say unto them: I am the Eternal your G-d, is as if He said, “Say unto them in My Name, ‘I am the Eternal your G-d.’” Similarly, Speak unto all the congregation of the children of Israel, and say unto them: Ye shall be holy, for I the Eternal your G-d am holy, [means: “say unto them in My Name, ‘Ye shall be holy'”].
It is possible that the reason [why the verse does not say: “this is what G-d commanded,” is not because it means: “say unto them in My Name” as explained above, but] is rather as follows: When Moses came out from before the Eternal without the veil [on his face], and he came out, and spoke unto the children of Israel that which he was commanded,, Verse 34. he did not need to say to them: “Thus said the Eternal,” for it was known to them that it was His spirit that spoke through him [Moses] and His word was upon his tongue, in My Name, I am the Eternal your G-d,” since it was known to them that Moses did not speak in his own name. and that he did not speak in his own name. Similarly, in many places in the Book of Deuteronomy it is stated in the same way, such as: And it shall come to pass, if ye shall hearken diligently unto My commandments, which I command you this day … that I will give the rain of your Land … And I will give grass in thy fields, and [it is known that] Moses is not the one who giveth rain upon the earth, and sendeth waters upon the fields, and makes the grass grow in the fields, but it is G-d, blessed be He [that does these things]. Similarly it is said, But the Eternal hath not given you a heart to know … And I have led you forty years in the desert … Ye have not eaten bread, neither have ye drunk wine or strong drink; that ye might know that I am the Eternal your G-d. …] clearly indicates that the expression in the following verse, And I have led you etc. is also a reference to the Eternal, and not to Moses. The meaning of the expression to love the Eternal your G-d, 11:13. [which is stated in the third person, when that same verse begins in the first person, And it shall come to pass, if ye shall hearken diligently unto My commandments], has already been explained.