1 Peter 3:15

The words "ready... to give an answer" and so forth must be connected with the words "show good conduct" ("have a good conscience"). For when you do this with meekness and propriety, then you yourselves will be assured that you have a good conscience, and …

That the Lord commands sanctification, that is, rest for the sake of loving, this is a purely moral precept. Whence blessed Peter says: But sanctify the Lord Christ in your hearts, that is, love him. For he sanctifies or makes holy the Sabbath who loves …

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 …

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 …

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 …

From the words of the prophet that he cited, he draws a conclusion. There it is said: "The eyes of the Lord are upon the righteous, and the face of the Lord is against those who do evil" (1 Pet. 3:12), and the apostle adds …

But sanctify the Lord God in your hearts - Have an holy fear, and a full trust in his wise providence. The hope - Of eternal life. With meekness - For anger would hurt your cause as well as your soul.

There may be a good reason given for religion; it is not a fancy but a rational scheme revealed from heaven, suited to all the necessities of miserable sinners, and centering entirely in the glory of God through Jesus Christ. Thirdly, Every Christian is bound to answer and apologize for the hope that is in him.

But sanctify the Lord God in your hearts,....

But sanctify the Lord God in your hearts - In Isaiah Isa 8:13 this is, “sanctify the Lord of hosts himself;” that is, in that connection, regard him as your Protector, and be afraid of him, and not of what man can do. The sense in the passage before us is, “In your hearts, or in the affections of the soul, regard the Lord God as holy, and act toward him with that confidence which a proper respect for one so great and so holy demands.

This refutes Rome's dogma, "I believe it, because the Church believes it." Credulity is believing without evidence; faith is believing on evidence. There is no repose for reason itself but in faith.

But sanctify the Lord God in your hearts - To sanctify God may signify to offer him the praises due to his grace, but as to sanctify literally signifies to make holy, it is impossible that God should be thus sanctified. We have often already seen that ἁγιαζω signifies to separate from earth, that is, from any common use or purpose, that the thing or person thus separated may be devoted to a sacred use. Perhaps we should understand Peter’s words thus: Entertain just notions of God; of his nature, power, will, justice, goodness, and truth. Do not conceive of him as being actuated by such passions as men; separate him in your hearts from every thing earthly, human, fickle, rigidly severe, or capriciously merciful. Consider that he can neither be like man, feel like man, nor act like man. Ascribe no human passions to him, for this would desecrate not sanctify him. Do not confine him in your conceptions to place, space, vacuity, heaven, or earth; endeavor to think worthily of the immensity and eternity of his nature, of his omniscience, omnipresence, and omnipotence. Avoid the error of the heathens, who bound even their Dii Majores, their greatest gods, by fate, as many well-meaning Christians do the true God by decrees; conceive of him as infinitely free to act or not act, as he pleases. Consider the goodness of his nature; for goodness, in every possible state of perfection and infinitude, belongs to him. Ascribe no malevolence to him; nor any work, purpose, or decree, that implies it: this is not only a human passion, but a passion of fallen man. […]