Genesis 1:26 New International Version (NIV)

26 Then God said, “Let us make mankind in our image, in our likeness, so that they may rule over the fish in the sea and the birds in the sky, over the livestock and all the wild animals, and over all the creatures that move along the ground.”

Why does God use the plural form? There are two possible views for this. First, this was stated in view of the Trinity. The Trinity is God the Father, Jesus Christ the Son, and the Holy Spirit. All Three are God. Another view is that the plural is used in reference to majesty. Kings traditionally used plural forms of words to refer to themselves. The grammar should not decide the matter because in either case, we know God created us in his image. God reveals himself to us as a Trinity. He does this clearly through all of the Scriptures.