In the gospel of John the Lord says: In this will all men know that you are my disciples, if you have love for each other. In a letter of the same apostle we read: Beloved, let us love one another, for love is from God, and everyone who loves is born of God and knows God; he who does not love does not know God, for God is love. The faithful should therefore enter into themselves and make a true judgment on their attitudes of mind and heart. If they find some store of love’s fruit in their hearts, they must not doubt God’s presence within them. If they would increase their capacity to receive so great a guest, they should practice greater generosity in doing good, with persevering charity. If God is love, charity should know no limit, for God cannot be confined.
From a sermon by Saint Leo the Great, pope