Second Clement, written circa A.D. 125, is the earliest known Christian sermon outside of the New Testament.

Brothers, we ought to think of Jesus Christ as we do of God, as “Judge of the living and the dead.” For he has given us the light; as a father he has called us sons; he saved us when we were perishing. What praise, then, shall we give him, or what repayment in return for what we received? Our minds were blinded, and we worshiped stones and wood and gold and silver and brass, the works of men; indeed, our whole life was nothing else but death. For he had mercy upon us and in his compassion he saved us when we had no hope of salvation.

But how do we acknowledge him? By doing what he says and not disobeying his commandments, and honoring him not only with our lips but “with our whole heart and with our whole mind.” And in Isaiah he also says, “This people honors me with their lips, but their heart is far from me.”

Let us, therefore, not just call him Lord, for this will not save us. For he says, “Not everyone who says to me, ‘Lord, Lord,’ will be saved, but only the one who does what is right.” So then, brothers, let us acknowledge him in our actions by loving one another, by not committing adultery or slandering one another or being jealous, but by being self-controlled, compassionate, and kind. And we ought to have sympathy for one another and not be avaricious.

For if we do the will of Christ, we will find rest; but if we do not, if we disobey his commandments, then nothing will save us from eternal punishment. And the Scripture also says in Ezekiel, “Even if Noah and Job and Daniel should rise up, they will not save their children” in the captivity. Now if even such righteous men as these are not able, by means of their own righteous deeds, to save their children, what assurance do we have of entering the kingdom of God if we fail to keep our baptism pure and undefiled?

Therefore, brothers, let us repent immediately. Let us be clearheaded regarding the good, for we are full of much stupidity and wickedness. Let us wipe off from ourselves our former sins and be saved, repenting from the very souls of our being. And let us not seek to please men. But let us not desire to please only ourselves with our righteousness, but also those who are outsiders, that the Name may not be blasphemed on our account. For the Lord says, “My name is continually blasphemed among all the nations,” and again, “Woe to him on whose account my name is blasphemed.”

Why is it blasphemed? Because you do not do what I desire. For when they [the pagans] hear from us that God says, “It is no credit to you if you love those who love you, but it is a credit to you if you love your enemies and those who hate you,” when they hear these things, they marvel at such extraordinary goodness. But when they see that we not only do not love those who hate us, but do not even love those who love us, they scornfully laugh at us, and the Name is blasphemed.

Let us repent, therefore, with our whole heart, lest any of us should perish needlessly. For if we have orders that we should make it our business to tear men away from idols and to instruct them, how much more wrong is it that a soul which already knows God should perish?

But do not let it trouble your mind that we see the unrighteous possessing wealth while the servants of God experience hardships. Let us have faith, brothers and sisters! We are competing in the contest of a living God, and are being trained by the present life in order that we may be crowned in the life to come.

“To the only God, invisible,” the Father of truth, who sent forth to us the Savior and Founder of immortality, through whom he also revealed to us the truth and the heavenly life, to him be the glory forever and ever. Amen.