John Gill Commentary Exodus 6:7

"and I will take you to me for a people, and I will be to you a God; and ye shall know that I am Jehovah your God, who bringeth you out from under the burdens of the Egyptians." — Exodus 6:7 (ASV)

And I will take you to me for a people Out of the hands of the Egyptians, and out of their country, to be in a political sense his kingdom and subjects; and in a religious sense a holy people to himself, to fear, serve, worship, and glorify him, by walking according to laws and rules given them by him; and this he did by setting up and establishing a civil and ecclesiastical polity among them:

and I will be to you a God ; their King and their God to rule over them, protect and defend them, they being a theocracy; and their covenant God and Father, giving them various spiritual privileges, the adoption, the glory, the covenant, the law, service, and promises:

and you shall know that I am the Lord your God ; by the promises fulfilled, the favours granted, and the deliverances wrought for them:

which bringeth you out from under the burdens of the Egyptians ; see the preceding verse (Exodus 6:6) .