Summary: Trying to follow the command of Jesus to love God and others without the power of the Spirit would be like trying to fill a bucket with water that has holes in the bottom of it. The bucket won't fill up.
If you sit down to a piano and play one key you create a sound. Now if you strike another key at the same time, you will have one of two tones. You will hear a harmonious tone, or you will hear a dissonant tone. You'll know right away which tone you hear. If you strike two keys at the same time that create a harmonious tone, it sounds good. If you strike middle C on a key board, and at the same time, strike the E key, you will hear a harmonious chord. It sounds good. It sounds like these tones go together. But if you strike the middle C on a key board and then at the same time strike the D key right next to it, you'll hear dissonance. The tone will not sound good. These two notes will not sound like they go together.
In music language when two notes are played at the same time that create dissonance and then one tone goes up or down and lingers or stops on a harmony, this movement from dissonance to harmony is called resolution. The chord has been resolved.
Keeping our attention on the keyboard let's create an analogy. Let's say that the trinity of God, Jesus and the Holy Spirit are in harmony. When God created Adam and Eve the Scripture says that God would walk the garden with them. God kept the harmony together. That would be like striking the middle C and the E key at the same time. It sounds nice. This is a harmonious tone. But we also know from Genesis that Adam and Eve disobeyed God. Sin creates dissonance. So Adam and Eve slipped down from the E key to the D key. If you play middle C and the key next to it this is dissonance. Where there was harmony, now there is a really annoying sound. We're told in the Bible that Jesus resolves the dissonance between us and God. Romans 5:18, "Adam’s one sin brings condemnation for everyone, but Christ’s one act of righteousness brings a right relationship with God and new life for everyone." God doesn't move. In the Old Testament, when God demands repentance from His children He begins by saying, "I don't change." God is always C, people without Jesus are D and they are in dissonance with God, and those who follow Jesus are E and are resolved through Jesus back into harmony with God.
Spiritually, this process is called Reconciliation. In short we can say God reconciles us through Jesus in that He takes us from dissonance with God to harmony.
For those of us who are in harmony with God there are benefits in this relationship. Paul discusses a few things that are blessings for Jesus followers who live in harmony, or who are reconciled with God and he begins this outline at the beginning of Romans 5.
I am blessed to be right with God because...
I enjoy peace with God. Romans 5:1-2 "Therefore, since we have been made right in God’s sight by faith, we have PEACE with God because of what Jesus Christ our Lord has done for us. Because of our faith, Christ has brought us into this place of undeserved privilege where we now stand, and we confidently and joyfully look forward to sharing God’s glory."