1 Peter 1:8

8Whom having not seen, or, Whom though ye have not seen. He lays down two things, that they loved Christ whom they had not seen, and that they believed on him whom they did not then behold. But the first arises from the second; for the cause of love is faith, not only because the knowledge of those blessings which Christ bestows on us, moves us to love him, but because he offers us perfect felicity, and thus draws us up to himself. He then commends the Jews, because they believed in Christ whom they did not see, that they might know that the nature of faith is to acquiesce in those blessings which are hid from our eyes. They had indeed given some proof of this very thing, though he rather directs what was to be done by praising them.

The first clause in order is, that faith is not to be measured by sight. For when the life of Christians is apparently miserable, they would instantly fail, were not their happiness dependent on hope. Faith, indeed, has also its eyes, but they are such as penetrate into the invisible kingdom of God, and are contented with the mirror of the Word; for it is the demonstration of invisible things, as it is said in Hebrews 11:1. Hence true is that saying of Paul, that

we are absent from the Lord while we are in the flesh;
for we walk by faith and not by sight.
(2 Corinthians 5:6.)

The second clause is, that faith is not a cold notion, but that it kindles in our hearts love to Christ. For faith does not (as the sophists prattle) lay hold on God in a confused and implicit manner, (for this would be to wander through devious paths;) but it has Christ as its object. Moreover, it does not lay hold on the bare name of Christ, or his naked essence, but regards what he is to us, and what blessings he brings; for it cannot be but that the affections of man should be led there, where his happiness is, according to that saying,

“Where your treasure is, there is also your heart.” (Matthew 6:21.)

Ye rejoice, or, Ye exult. He again refers to the fruit of faith which he had mentioned, and not without reason; for it is an incomparable benefit, that consciences are not only at peace before God, but confidently exult in the hope of eternal life. And he calls it joy unspeakable, or unutterable, because the peace of God exceeds all comprehension. What is added, full of glory, or glorified, admits of two explanations. It means either what is magnificent and glorious, or what is contrary to that which is empty and fading, of which men will soon be ashamed. Thus “glorified” is the same with what is solid and permanent, beyond the danger of being brought to nothing. (13) Those who are not elevated by this joy above the heavens, so that being content with Christ alone, they despise the world, in vain boast that they have faith.