John Gill Commentary Deuteronomy 14:2

"For thou art a holy people unto Jehovah thy God, and Jehovah hath chosen thee to be a people for his own possession, above all peoples that are upon the face of the earth." — Deuteronomy 14:2 (ASV)

For you are an holy people unto the Lord your God
Set apart by him from all other people, and devoted to his worship and service, and many of them were sanctified and made holy in a special and spiritual sense; and therefore should not conform to the customs of Gentiles, whether in their extravagant mourning for the dead, or in their religious services; see (Deuteronomy 7:6) ,

and the Lord has chosen thee to be a peculiar people, above all the
nations that [are] upon the earth ;
to be his peculiar treasure, to be his peculiar servants and worshippers, to enjoy peculiar blessings and privileges, and behave in a peculiar manner different from all other people; and have no connection with them, especially in things sacred; and, in order to keep them a distinct peculiar people from all others, a peculiar diet was appointed them, that so being prohibited to eat such things as others did, they might be kept out of their company and conversation, and so from being drawn into their idolatrous practices; the rules concerning which follow; see (Deuteronomy 7:6) .