From the beginning of creation in Genesis to the end of times in Revelation, God refers to Himself as "us" or "our" and thus describes the doctrine of the Trinity. The word trinity comes from "tri" meaning three and "unity" meaning one. God is three distinct individuals - God the Father, the Son Jesus, and the Holy Spirit - in one true God. The below Bible verses and Scriptures about the trinity will help you have a better understanding of who God is. It can be a difficult concept to grasp, yet we can believe God's word and know that while His ways are higher than ours, we can trust in Him!
For further research, read "God in Three Persons - The Trinity Explained"