15 For both to prophesy and to cast out devils, and to do great acts upon the earth is certainly a sublime and an admirable thing; but one does not attain the kingdom of heaven although he is found in all these things, unless he walks in the observance of the right and just way. The Lord denounces, and says, “Many shall say to me in that day, Lord, Lord, have we not prophesied in Your name, and in Your name have cast out devils, and in Your name done many wonderful works?
And then will I profess unto them, I never knew you: depart from me, you that work iniquity.” There is need of righteousness, that one may deserve well of God the Judge; we must obey His precepts and warnings, that our merits may receive their reward. The Lord in His Gospel, when He would direct the way of our hope and faith in a brief summary, said, “The Lord your God is one God: and you shall love the Lord your God with all your heart, and with all your soul, and with all your strength.
This is the first commandment; land the second is like it: You shall love your neighbour as yourself. On these two commandments hang all the law and the prophets.” He taught, at the same time, love and unity by His instruction. He has included all the prophets and the law in two precepts. But what unity does he keep, what love does he maintain or consider, who, savage with the madness of discord, divides the Church, destroys the faith, I disturbs the peace, dissipates charity, profanes the sacrament?
Source: The Treatises of Cyprian (New Advent)