2 From which an example is given us to avoid the way of the old man, to stand in the footsteps of a conquering Christ, that we may not again be incautiously turned back into the nets of death, but, foreseeing our danger, may possess the immortality that we have received. But how can we possess immortality, unless we keep those commands of Christ whereby death is driven out and overcome, when He Himself warns us, and says, “If you will enter into life, keep the commandments?” And again: “If you do the things that I command you, henceforth I call you not servants, but friends.” Finally, these persons He calls strong and steadfast; these He declares to be founded in robust security upon the rock, established with immoveable and unshaken firmness, in opposition to all the tempests and hurricanes of the world.
“Whosoever,” says He, “hears my words, and does them, I will liken him unto a wise man, that 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.” We ought therefore to stand fast on His words, to learn and do whatever He both taught and did. But how can a man say that he believes in Christ, who does not do what Christ commanded him to do? Or whence shall he attain to the reward of faith, who will not keep the faith of the commandment? He must of necessity waver and wander, and, caught away by a spirit of error, like dust which is shaken by the wind, be blown about; and he will make no advance in his walk towards salvation, because he does not keep the truth of the way of salvation.
Source: The Treatises of Cyprian (New Advent)