The text is clear: God planned to make all mankind in His image, and then He carried out His plan by creating man and woman. We know that “man” in Genesis 1:26 refers to mankind collectively by God’s use of the plural “they”, as those who will rule over the created world. Then in Genesis 1:27, God narrows in and creates one singular man and woman. He intends to create all of mankind in the image of God, and He begins His image-bearing creation with a man and woman—both made in God’s likeness.
God will sanctify me. He will grow me to become more like Him, so others will know of His greatness; “he will surely do it.” This will happen in the believer’s life because HE is faithful.