That we must labour not with words, but with deeds
In Solomon, in Ecclesiasticus: “Be not hasty in your tongue, and in your deeds useless and remiss.” And Paul, in the first to the Corinthians: “The kingdom of God is not in word, but in power.” Also to the Romans: “Not the hearers of the law are righteous before God, but the doers of the law shall be justified.” Also in the Gospel according to Matthew: “He who shall do and teach so, shall be called greatest in the kingdom of heaven.” Also in the same place: “Every one who hears my words, and does them, I will liken him to a wise man who built his house upon a rock. The rain descended, the floods came, the winds blew, and beat upon that house, and it fell not: for it was founded upon a rock. And every one who hears my words, and does them not, I will liken him to the foolish man, who built his house upon the sand. The rain descended, the floods came, the winds blew, and beat upon that house; and it fell: and its ruin became great.”
Source: The Treatises of Cyprian (New Advent)