Clement’s (died c.100 A.D), presbyter and bishop of Rome, letter to the Corinthians is probably one of the earliest Christian writings outside the New Testament. It’s in his letters were you find important evidences of Paul’s mission to Spain and also the martyrdom of Peter and Paul.
One of remarkable passage I came across that I wish to share is the praise of love that is in Christ Jesus:
Let him who has love in Christ keep the commandments of Christ. Who can describe the [blessed] bond of the love of God? What man is able to tell the excellence of its beauty, as it ought to be told? The height to which love exalts is unspeakable. Love unites us to God. Love covers a multitude of sins. Love beareth all things, is long-suffering in all things. There is nothing base, nothing arrogant in love. Love admits of no schisms: love gives rise to no seditions: love does all things in harmony. By love have all the elect of God been made perfect; without love nothing is well-pleasing to God. In love has the Lord taken us to Himself. On account of the Love he bore us, Jesus Christ our Lord gave His blood for us by the will of God; His flesh for our flesh, and His soul for our souls.
To that I will add first epistle of John:
Whoever confesses that Jesus is the Son of God, God abides in him, and he in God.So we have come to know and to believe the love that God has for us. God is love, and whoever abides in love abides in God, and God abides in him.By this is love perfected with us, so that we may have confidence for the day of judgment, because as he is so also are we in this world.There is no fear in love, but perfect love casts out fear. For fear has to do with punishment, and whoever fears has not been perfected in love.We love because he first loved us (1 John 4:16-20 ESV)
May the awesomely infinity, unspeakable and unfailing love unites us to God.
The Ante-Nicene Fathers, Volume I: The Apostolic Fathers with Justin Martyr and Irenaeus. 1885 (A. Roberts, J. Donaldson & A. C. Coxe, Ed.) (p. 18). Buffalo, NY: Christian Literature Company.