Adam Clarke on Psalms 100:3

Know ye that the Lord he is God - Acknowledge in every possible way, both in public and private, that Jehovah, the uncreated self-existent, and eternal Being, is Elohim, the God who is in covenant with man, to instruct, redeem, love, and make him finally happy.

It is he that hath made us - He is our Creator and has consequently the only right in and over us.

And not we ourselves - ולא אנחנו velo anachnu. I can never think that this is the true reading, though found in the present Hebrew text, in the Vulgate, Septuagint, Ethiopic, and Syriac. Was there ever a people on earth, however grossly heathenish, that did believe, or could believe, that they had made themselves? In twenty-six of Kennicott's and De Rossi's MSS. we have ולו אנחנו velo anachnu, "and His we are;" לו lo, the pronoun, being put for לא lo, the negative particle. This is the reading of the Targum, or Chaldee paraphrase ודיליה אנחנא vedileyh anachna, "and his we are," and is the reading of the text in the Complutensian Polyglot, of both the Psalters which were printed in 1477, and is the keri, or marginal reading in most Masoretic Bibles. Every person must see, from the nature of the subject that it is the genuine reading. The position is founded on the maxim that what a man invents, constructs out of his own matterials, without assistance in genius, materials or execution from any other person, is His Own and to it, its use, and produce, he has the only right. God made us, therefore we are His: we are his people, and should acknowledge him for our God; we are the sheep of his pasture, and should devote the lives to him constantly which he continually supports.