This is a quotation from the book of Psalms which says "Yahweh said to my Lord." But the Jews stopped saying "Yahweh" and often said "Lord" instead. Alternate translation: "The Lord God said to my Lord" or "God said to my Lord"
To sit at the "right hand of God" is a symbolic action of receiving great honor and authority from God. Alternate translation: "Sit in the place of honor beside me" (See: [[rc://en/ta/man/jit/translate-symaction]])