Afflicted - The affliction meant here is less that of outward circumstances than of a troubled and downcast spirit. Life to the cheerful is as one perpetual banquet, whether he be poor or rich. That which disturbs the feast is anxiety, the taking (anxious) thought" of Matthew 6:34.

All the days of the afflicted are evil,.... And some are afflicted all their days, from their youth up; so that not only the days of old age are evil days, in which they have no pleasure, but even the days of their youth; all their days, as Jacob says, "few and evil have the days of the years of my life been", Genesis 47:9; because they had been filled up with affliction and trouble of one sort or another. Or, "all the days of the poor" (f); either in purse, who want many of the good things of life; or in knowledge, as Gersom and Aben Ezra observe;
but he that is of a merry heart hath a continual feast; a heart that has "the kingdom of God" in it, which lies "not in meat and drink, but in righteousness, peace, and joy in the Holy Ghost", Romans 14:17, which has the love of God shed abroad in it by the Spirit, where Christ dwells by faith; and that lives by faith on him, and on the provisions of his grace; all this is a constant continual feast to a gracious soul, made joyful hereby.
(f) "pauperis", V. L. Pagninus, Junius & Tremellius, Piscator, Mercerus, Michaelis.

Some are much in affliction, and of a sorrowful spirit. Such are to be pitied, prayed for, and comforted. And others serve God with gladness of heart, and it prompts their obedience, yet they should rejoice with trembling.

The state of the heart governs the outward condition.
evil--sad, contrasted with the cheerfulness of a feast.

15 All the days of the afflicted are evil;
But he who is of a joyful heart hath a perpetual feast.
Regarding עני (the afflicted), vid., 21b. They are so called on whom a misfortune, or several of them, press externally or internally. If such an one is surrounded by ever so many blessings, yet is his life day by day a sad one, because with each new day the feeling of his woe which oppresses him renews itself; whoever, on the contrary, is of joyful heart (gen. connection as Proverbs 11:13; Proverbs 12:8), such an one (his life) is always a feast, a banquet (not משׁתּה, as it may be also pointed, but משׁתּה and תּמיד thus adv., for it is never adj.; the post-bib. usage is תּמידין for עולות תּמיד). Hitzig (and also Zckler) renders 15b: And (the days) of one who is of a joyful heart are.... Others supply לו (cf. Proverbs 27:7), but our rendering does not need that. We have here again an example of that attribution (Arab. isnâd) in which that which is attributed (musnad) is a condition (hal) of a logical subject (the musnad ilêhi), and thus he who speaks has this, not in itself, but in the sense of the condition; the inwardly cheerful is feasts evermore, i.e., the condition of such an one is like a continual festival. The true and real happiness of a man is thus defined, not by external things, but by the state of the heart, in which, in spite of the apparently prosperous condition, a secret sorrow may gnaw, and which, in spite of an externally sorrowful state, may be at peace, and be joyfully confident in God.

Afflicted - Of the troubled in mind. Evil - Tedious and uncomfortable. Chearful - Hebrews. of a good heart.