Andreas of Caesarea : Just as magnifying God cannot add anything to his greatness and glorifying him does not make him any more glorious, so sanctifying the Lord does not mean that there is any addition to his existing holiness. Rather we are called to sanctify him in our hearts, and if we form a clear understanding of his holiness, then we do not sanctify him on one occasion only, but rather by doing this we have a better understanding of what his holiness is and something of it is implanted in our hearts. Likewise someone who magnifies God receives a share of his greatness, and someone who glorifies him is glorified in turn. It is a prophetic voice which says that there should be no fear in you which might prevent you from confessing Christ in your hearts. You should sanctify him there also. For this confession is sanctification both for the soul and for the body. Some people wonder why the Savior said: "Do not worry about what you will say," but here the apostle writes: "Be ready to give an explanation." However, there is no contradiction. Jesus was speaking about bearing witness, whereas Peter is talking about teaching others the faith. — CATENA Augustine of Hippo : The apostle tells us to be ready to give an answer to anyone who asks us for an explanation of our faith, because if an unbeliever asks me a reason for my faith and hope and I perceive that he cannot accept it unless he believes, I give him that very reason, so that he may see how absurd it is for him to ask a reason for things which he cannot grasp until he believes. — LETTERS 120 Bede : Sanctify the Lord Christ in your hearts. What does it mean to sanctify the Lord in our hearts, if not to contemplate His holiness, which is of incomprehensible glory, with the innermost affection of the heart? How much strength He is able to give to those hoping in Him to overcome, whose inestimable holiness shines forth. — Commentary on the Catholic Epistles Bede : Always be prepared to provide an answer to everyone who asks you to give the reason for the hope that you have. We must be prepared to give an account of our hope and faith to those who ask in two ways, so that we may reveal the just reasons for our hope and faith to everyone, whether they inquire faithfully or unfaithfully, and so that we always hold firm the very profession of our faith and hope, even amidst the pressures of adversaries, showing by patience how reasonably we have learned to maintain it, for the love of which we neither fear to suffer adversities nor to undergo death. — Commentary on the Catholic Epistles Clement of Alexandria ((as quoted by Cassiodorus)) : "But sanctify the Lord Christ," he says, "in your hearts." For so you have in the Lord's prayer, "Hallowed be Thy name." — From the Latin Translation of Cassiodorus Cyril of Alexandria : The one who decides to do this is not doing anything new, nor is he making up some new explanation. Rather he is making clear to those who ask him what his faith in Christ is all about. — LETTERS 40.8 Didymus the Blind : We must be so well instructed in the knowledge of our faith that whenever anyone asks us about it we may be able to give them a proper answer and to do so with meekness and in the fear of God. For whoever says anything about God must do so as if God himself were present to hear him. — CATENA Oecumenius : Furthermore, God commands "to sanctify Him in the hearts," as Isaiah says (Is. 8:13): this means, do not glory in those things that appear, but in the hidden treasury of your hearts, working the sanctification of the Lord, which consists in the separation of the nations from their abominations or wicked customs; thus sanctify Him. However, being sanctified, while others glorify Him through your good conduct, just as God and man Himself commands when He says: "Let your light shine before men," etc. (Matt. 5:16) What is said about being ready is connected to the previous part, for example, "all of you, be united." The word "be" is also attributed to the common understanding, so the meaning is: "May you always be ready." He wants to command that a faithful person should always be prepared regarding the discourse of faith, so that at any time when a reason concerning it is sought from us, we may easily respond; moreover, in responding, let us do so with meekness, as if God Himself were present: no diligent servant would be arrogant in the presence of his master. It also adds the profit that follows from this, namely, the inquiry of the unbelievers and the kindness of the mind towards us. However, it should be noted that these are not contrary to what has been said by the Lord, for He indeed commands not to be anxious about what we should answer when we are brought before rulers and authorities. (Matt. 10:19) Indeed, the Lord's words about martyrdom were spoken, as He also says that virtue and a more powerful discourse should be given than any human wisdom, and that one who despises the surrounding fears: however, Peter's opinion speaks of doctrine. For without understanding and inquiry, it is worthy of reproach to think one knows something. For the knowledge of the foolish is an unprofitable discourse. (Eccles. 21:21) Moreover, since we were accused of various wicked things, and they also showed that our hope was vain, he says that we should bring forth considered responses about these things, having at the same time a proven life, which he certainly calls conscience. — Commentary on 1 Peter