Ibn Ezra

ידי Mine hand. My left hand. It is a figurative expression; the right hand is used in connection with the heavens, because they are higher in rank than the earth. אף has in this verse the same meaning as כי for.—It is true that I am the first and last, because I created every thing. טפחה Hath put round, Comp. טפחתי I have swaddled (Lam. 2:22). Others explain it: Hath measured with the handbreadth יעמדו יחדיו —.(טֶפַח) They stand up together. From this phrase some of the commentators derive their opinion, that heaven and earth were created simultaneously, not consecutively. The literal meaning, however, is: I have made them, and when I call them to do My will and desire they stand both before Me like servants; comp. למשפטיך עמדו they stand up according to Thy ordinances (Ps. 119:91). For else how should God call them, when not yet existing.