James 1:2

2All joy. The first exhortation is, to bear trials with a cheerful mind. And it was especially necessary at that time to comfort the Jews, almost overwhelmed as they were with troubles. For the very name of the nation was so infamous, that they were hated and despised by all people wherever they went; and their condition as Christians rendered them still more miserable, because they held their own nation as their most inveterate enemies. At the same time, this consolation was not so suited to one time, but that it is always useful to believers, whose life is a constant warfare on earth.

But that we may know more fully what he means, we must doubtless take temptations or trials as including all adverse things; and they are so called, because they are the tests of our obedience to God. He bids the faithful, while exercised with these, to rejoice; and that not only when they fall into one temptation, but into many, not only of one kind, but of various kinds. And doubtless, since they serve to mortify our flesh, as the vices of the flesh continually shoot up in us, so they must necessarily be often repeated. Besides, as we labor under diseases, so it is no wonder that different remedies are applied to remove them.

The Lord then afflicts us in various ways, because ambition, avarice, envy, gluttony, intemperance, excessive love of the world, and the innumerable lusts in which we abound, cannot be cured by the same medicine.

When he bids us to count it all joy, it is the same as though he had said, that temptations ought to be so deemed as gain, as to be regarded as occasions of joy. He means, in short, that there is nothing in afflictions which ought to disturb our joy. And thus, he not only commands us to bear adversities calmly, and with an even mind, but shews us that this is a reason why the faithful should rejoice when pressed down by them.

It is, indeed, certain, that all the senses of our nature are so formed, that every trial produces in us grief and sorrow; and no one of us can so far divest himself of his nature as not to grieve and be sorrowful whenever he feels any evil. But this does not prevent the children of God to rise, by the guidance of the Spirit, above the sorrow of the flesh. Hence it is, that in the midst of trouble they cease not to rejoice.