Again, One MUST have knowledge of Hebrew (majestic plurals, pronouns).
Genesis 1:26
One of the most popular verses used by missionaries as a proof text in support of the doctrine of the Trinity is Genesis 1:26. This verse appears frequently in missionary literature despite of the fact that this argument has been answered countless times throughout the centuries and numerous Christian scholars have long abandoned it. Let’s examine the creation of man as described in the Torah.
With limited knowledge of the Jewish Scriptures, missionaries submit the above verse as evidence that there was a plurality in the godhead that participated in creation of our first parent. What other explanation could adequately account for the Torah’s use of the plural pronouns such as “us” and “our” in this verse?
This argument, however, is deeply flawed, and, accordingly, a great number of Trinitarian theologians have long rejected the notion that Genesis 1:26 implies a plurality of persons in the godhead. Rather, Christian scholars overwhelmingly agree that the plural pronoun in this verse is a reference to God’s ministering angels who were created previously, and the Almighty spoke majestically in the plural, consulting His heavenly court. Let’s read the comments of a number of preeminent Trinitarian Bible scholars on this subject.
The answer emerges from the Torah and its Prophets. If you search the Hebrew Bible you will find that when the Almighty speaks of “us” or “our,” He is addressing His ministering angels. In fact, only two chapters later, God continues to use the pronoun “us” as He speaks with His angels. At the end of the third chapter of Genesis the Almighty relates to His angels that Adam and his wife have eaten from the Tree of Knowledge and must therefore be prevented from eating from the Tree of Life as well; for if man would gain access to the Tree of Life he will “become like one of us.” The Creator then instructs his burning angels, known as Cherubim, to stand at the entrance to the gate of the Garden of Eden, waving a flaming sword to prevent man from entering the Garden and eating from the Tree of Life.
Full answer here: http://outreachjudaism.org/trinity-genesis