When we think of love, it is in stages. First, we love, and most of us love and mess up, we love each other but we hurt each other, frustrate each other.
As life grows, as friendships grow and as marriages grow, the love should become perfected. At least to the point where we do not want to mess it up by our selfishness.
Jesus, in the Gospel says that if we love Him we will keep His commandments. This is actually us growing in love. We mess up but we continually go to confession and perfect ourselves. We hopefully learn from our mistakes. Jesus says, after He has taught us all, He will send the advocate the Holy Spirit to continue to teach us how to perfect that love. How to keep the commandments and not be selfish.
This is so important because the Holy Spirit is the Love of the Father and the Son alive. It is the living love of them alive in the third person of the Trinity. This love is now available to us as Jesus lived a selfless love for us.
When we live guided by the Holy Spirit, we live in the Love of Jesus and the Father and the love Jesus gives us. This is why Paul and Barnabas were able to do miracles in the first reading. The perfected and lived that love, they lived in the Holy Spirit.
Point being today, are we allowing the Holy Spirit to continue to teach us? This is what the saints did, they allowed the Holy Spirit to help them grow from imperfect love to perfect love, and fully keeping the commandments.
This is what we should be doing and aiming to do. When we do not, This is what purgatory is. It is the opposite of selfishness. Each commandment we do not keep fully is selfishness of some sort. Purgatory is a place to get rid of selfishness and purify it.
When we grow more deeply in love with Jesus by perfecting the commandments, and allowing the Holy Spirit to direct us in doing that, Jesus will reveal Himself to us more deeply here on earth and then for eternity.