Many people have a difficult time understanding the concept of how God can be three, yet One. Many attempts have been made to help people understand how God can be God the Father, God the Son and God the Holy Spirit, yet still be God as One. This is what the Lord showed me, and I hope it will help you to understand.
Picture an aged man sitting in His rocker on the porch of his home. His child is playing in the yard. Suddenly he hears a cry. The child has fallen and injured himself. The father rises up from his rocker, goes to the child, and stooping down, picks the child up, takes him back to the rocker, all the while speaking words of comfort and correction to the child.
This action has three different aspects. You have the father hearing and seeing, the father going and 'rescuing,' and the father speaking words of comfort to the child in his arms. There was only one person involved, yet the entire operation engaged three different aspects of his being. We, being made in the image of God are no different in this respect.
Now to explain the trinity. God the Father is the one who sees, the one who hears and the one who sends. God the Son is the one who goes, embraces and delivers. God the Holy Spirit is the one who speaks words of comfort and correction. You cannot remove any one of those aspects and have what you would call 'salvation.' Without the Father, there is no Son to go, nor Holy Spirit to speak. Without the Holy Spirit, there is no understanding of what happened or how to avoid it. And without the Father, there is no one paying any attention to you at all. Without all three acting together in One mission, with one purpose and intent, there would be only conflict and confusion.
All three apsects of God are needed for the outworking of our salvation. We need God, for without God there is no hearing of our cries and pleas for help. Without the Son, there is no one to do anything about our situation. And without the Holy Spirit, we have no knowledge of what just happened or how to avoid it in future. God is so beyond our comprehension, it would be impossible for Him to reveal to us all He is, without giving us these three representations of Himself. Furthermore, He would be unable to communicate the triunity of the Godhead, nor what it meant to be made 'in His image" as a triunity of spirit, soul and body unless He came in three different forms.
God desires that the fullness of His life, His godhead' be made manifest in us, but it must first begin by believing God is a tri-unity. You cannot call upon a Son if you do not believe, and He cannot send the Holy Spirit if you do not believe or desire Him. All three apsects of God are required to bring about what God has willed and purposed in the creating of man, the sending of His Son and the restoring of His Holy Spirit in us.