John Calvin Commentary Isaiah 3:10

"Say ye of the righteous, that [it shall be] well [with him]; for they shall eat the fruit of their doings." — Isaiah 3:10 (ASV)

Say, it shall be well with the righteous. Before quoting the opinions of others, I will point out the true meaning. Since such severe punishments commonly present an exceedingly sharp temptation to devout minds, and especially because hardly any public calamities occur that do not involve good people along with the bad, the Prophet—at least, in my opinion—reminds them of God's providence. This providence never mixes things up indiscriminately; even when there is apparent confusion, it never ceases to distinguish between good and bad people.

But there are various ways in which this passage is explained. Some render it, “Say to the righteous man, because he is good, therefore he shall eat the fruit of his hands.” From that interpretation, this meaning is obtained: “I wish and command the godly to be of good cheer; for however severely I may punish the crimes of the nation, it will still be well with the godly.” But a more suitable meaning is this: Say; that is, hold it to be a settled point. For in Scripture, to say often means to think and to be convinced, as David writes, I said, I will take heed to your ways (Psalms 39:1), and in a thousand similar instances. So, he does not command them to tell the righteous man, but he commands everyone to be fully convinced that the condition of the righteous man will be happy, even though he may only appear to be unhappy.

Besides, I consider טוב (tob) to mean a happy and prosperous condition, as in the previous verse he used the word רעה (ragnah), with which טוב is now contrasted. Thus, I do not think that רעה (ragnah) means wickedness, but a miserable condition.

Now, since it literally reads, Say to the righteous man, כי טוב (ki tob): that it shall be well, either the particle כי (ki) has an affirmative sense, as in many other passages, or it appears to be superfluous, although it is probable that it is intended for confirmation. Surely it shall be well with the righteous man; that is, let every reason for doubt be removed, and let us be fully convinced that the condition of the righteous man will be most excellent and prosperous.

It is difficult to believe this, and therefore it is added, he shall eat the fruit of his doings; that is, he will not be defrauded of the reward for his good conduct. Others consider to say as meaning to exhort, and render the two words כי טוב (ki tob) that he will do well; but I reject this as a forced interpretation.