One has to see at least four things in order to behold the glorious truth of God’s love for God. First, one has to understand some basic things concerning the Trinity. Second, one must understand that the Father loves and shines His glory in and through the Son and the Son loves the Father. According to Hebrews 1:3, the Son is the very shining forth of the glory of God. Third, that Jesus Christ is very God of very God even when clothed in human flesh, which is to say that the second Person of the Trinity was united to a human body in such a way that the human body manifested the glory of God as the Spirit worked in the humanity of Christ. Four, the Holy Spirit is at the very least the power behind all acts of love. A fifth part could be added and that is all the evidence from Scripture that God does all for Himself, His name’s sake, and His own glory. When the fifth part is seen in light of the nature of the Trinity, it is inescapable that God loves Himself and does all things out of that love for Himself. So the four things are necessary to see this great truth, but the fifth adds luster and more weight to the case.
In setting out some of the basic truths of the Trinity it should be noted that there have been books written on this subject so only the basics can be set out in this setting. The most basic truth of the Trinity is that there is only one God who exists in three Persons. To put it differently, the way that the one God exists is in three Persons or the three Persons exist as one God. God the Father, God the Son, and God the Holy Spirit are one in nature. They all have one nature and share in that nature and are all one in that nature. Therefore, if it can be shown from Scripture that the Father loves the Son and that the Son loves the Father, it will then be easily seen that God loves Himself.
Deuteronomy 6:4 “Hear, O Israel! The LORD is our God, the LORD is one!
1 Corinthians 8:6 yet for us there is but one God, the Father, from whom are all things and we exist for Him; and one Lord, Jesus Christ, by whom are all things, and we exist through Him.
Ephesians 4:5 one Lord, one faith, one baptism, 6 one God and Father of all who is over all and through all and in all.
1 Timothy 2:5 For there is one God, and one mediator also between God and men, the man Christ Jesus,
The Scriptures are so very clear that there is only one God. The worship of any other idea or concept or idol is nothing less than idolatry and is a violation of the First Command which is the command not to have any other gods before Him (in His presence). In reality there is no other real God, but the hearts of human beings are idol factories in that they constantly find things to love, worship, and trust rather than God. Throughout the history of the nation of Israel what got them into trouble over and over again was their propensity to worship other gods. It is not just that the doctrine of the Trinity sets out that there is one God, but that this teaching demands all from human beings. For example, the famous saying from Deuteronomy 6:4 is just before the giving of the Ten Commandments and is given as a reason the people should keep them. It is because God is one God and it is because He is who He is and how He is that the commandments are what they are and that is also why people should keep them. Indeed the New Testament gives other reasons for why the Law was given, but for the moment we are to take the text in its context.
The passage from I Corinthians 8:6 also teaches us that there is only one God, but it expands that teaching into who Christ is, though this is not the place for going into that. For the moment, however, notice that the fact that there is only one God is not a piece of bare information that is to fit into the brain alone. It is because there is one God that all things are from Him (including ourselves) and we exist for Him. It is impossible to escape the basic teaching of Scripture that there is one God, and yet that fact makes a huge moral demand on us. Because of that we owe all allegiance to Him and we are commanded to love Him with all of our being. Regardless of how this one God exists, our all is demanded by Him. Notice in the text below the concept that there is one God, but it then moves to the fact that all are then commanded to love Him with the heart and the whole being.
Mark 12:29 Jesus answered, “The foremost is, ‘HEAR, O ISRAEL! THE LORD OUR GOD IS ONE LORD; 30 AND YOU SHALL LOVE THE LORD YOUR GOD WITH ALL YOUR HEART, AND WITH ALL YOUR SOUL, AND WITH ALL YOUR MIND, AND WITH ALL YOUR STRENGTH.’ 31 “The second is this, ‘YOU SHALL LOVE YOUR NEIGHBOR AS YOURSELF.’ There is no other commandment greater than these.”
Now, looking ahead just a bit we can see from these passages that there is one God and what this one God demands. However, there is a lot implied and a lot hidden in these passages. These commands are meant to drive us to a Savior who is the one God, yet we need to know more. We also know from I John that the only way we can truly love God is if He puts that in us. This teaches us that we must have the Holy Spirit who can work the fruit love in our souls. We also don’t have it explicitly set before us the reason why this command is given and we are not told that this command is given as a reflection of who God is. The standard for holiness in both Testaments is to be holy as He is holy. So in this standard of holiness given to human beings (Great Commands) we are given something of how God is toward Himself. God lives in perfect love and human beings are commanded to love Him in a way that reflects His love for Himself and His own glory.