Origin of concept of triune God

When did the concept of a triune God come into being?

There never was a beginning to the triune God’s existence. God is eternal, without beginning and without end (Psalm 90:2).

People came to a knowledge of the unique nature of God when God revealed that in his word—as early as the first verse of the Bible: “In the beginning God created the heavens and the earth” (Genesis 1:1). In the original Hebrew, “God” in that verse is plural in form. That is a tip-off right there to the plurality of persons in the Godhead.

Later in the chapter “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’” (Genesis 1:26). Note the plural pronouns in that verse.

As time went on, God revealed more information about himself as a triune God. That information became clearest in the New Testament, with these words from Jesus’ great commission: “Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit…” (Matthew 28:19).

The eternal God is triune. We know that because he has revealed that information to us in his word.