Who among men knows the thoughts of a man except his spirit within him? In the same way no one knows the thoughts of God except the Spirit of God. We have not received the spirit of the world but the Spirit who is from God, that we may understand what God has freely given us. (I Corinthians 2:11)
If we receive the Spirit of God and Paul says this is God's Spirit in the same way that our own spirits know our own thoughts ... then it follows that we can understand the things of God and the nature of God by this Spirit.
What happens if you take that idea and connect it with the fruit of the Spirit?
The fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control. (Galatians 5:22-23)
If that is the fruit of the Spirit, and if the Spirit is the mind of God, then the mind of God naturally produces love, joy, peace, patience, kindness, goodness, faithfulness,gentleness, and self-control. The reason that God's Spirit produces them in us is that these things belong to God's nature. It is what God is truly like.
All things that fulfill the law are things that restore in us the image of God. Love does no harm to its neighbor and love is the fulfillment of the law. Love is the nature of God. We have seen before how God is holy and so his people are called to be holy, how God's people are called to follow his paths, how salvation is being restored in the image of God. From the nature of the Holy Spirit, it should follow that the nature of God includes everything that is named as fruit of the Spirit: love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control.
God is good.