What’s In A Word?
The use of the word “Elohim” for God has been hotly debated for centuries concerning the Trinity. To be fair, it has also been used of angels and false deities (including wood, stone, and gold idols etc) as well, so its use and meaning is defined by its context. I was reading through Genesis One the other day and found an interesting commentary concerning Elohim (emphasis mine):
An eminent Jewish rabbi, Simeon ben Joachi, in his comment on the sixth section of Leviticus, has these remarkable words: “Come and see the mystery of the word Elohim; there are three degrees, and each degree by itself alone, and yet notwithstanding they are all one, and joined together in one, and are not divided from each other.” See Ainsworth. He must be strangely prejudiced indeed who cannot see that the doctrine of a Trinity, and of a Trinity in unity, is expressed in the above words. 
There can be no doubt that the Elohim in the first chapter of Genesis is God speaking. Even though this quote of the rabbi Simeon ben Joachi is a commentary on Leviticus, it’s clear that this reference is of God. As you can see here, this rabbi inadvertently defines the Trinity! A further clarification on these degrees (persons) is when God speaks in plural pronouns such as “us” and “our” etc. In Genesis 1:26 we have a great example of such language.  Some have tried to get around the obvious by claiming that these are examples of the “plural of majesty”. The problem is however, that, the plural of majesty did not exist in the Hebrew scriptures . In reality, such language was not in use until the Byzantine era in the 4th century.  To recap, when we read where God said “Let us make man in our image”, we can safely say that this is the Trinity speaking; creating man in the image of God.
1. Adam Clarke’s Commentary On The Bible (e-Sword)
2. (King James Version) Genesis 1:26 And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth.
3. Uniplurality In The Hebrew Scriptures