the Bible never mentions the trinity in as many words. There was actually a scripture (which eludes me right now) which was amended by the church 100s of years ago, but is publically acknowledged to have been done so, in which the word trinity is used.
as before, there are only about 40 amendments that have been made to the new testament, all clearly marked, since its original writing.
nonetheless, anyone reading the bible will come across, time and again, the unity of the Godhead. Even in Genesis 1:26, it states
26 Then God said, "Let
us make man in
our image, in our likeness...
and also Genesis 1:1 the word used in the Hebrew for God is "Elohim," which is a form of the word "El." In the context of Genesis 1:1, there can be no doubt as to who is doing the creating. In the Hebrew language the "im" ending imputes plurality. Therefore, "Elohim" is the plural from of the word "El."
When confronted with this passage, modern rabbis often claim that God is speaking to the angels. However, this explanation fails to recognize a number of problems.
First, there is no indication in the Bible that angels can create life. Secondly, nowhere is it indicated that angels are made in the image of God. Finally, there is no indication that mankind was made in the image of angels either!
We may conclude that the person with whom Elohim is conversing lives in the eternal realm, has His creative power and exists in the image or likeness of God. No angel, no man, no created being in heaven or on earth could possibly fit these criteria.
I paraphrased / copied some of that from
here