What man is he that desireth life? - That desires to live long. All people naturally love life; and all naturally desire to live long; and this desire, being founded in our nature, is not wrong. Life is, in itself, a good - a blessing to be desired; death is in itself an evil, and a thing to be dreaded, and there is nothing wrong, in itself, in such a dread. Equally proper is it to wish not to be cut down in early life; for where one has before him an eternity for which to prepare, he feels it undesirable that he should be cut off in the beginning of his way. The psalmist, therefore, does not put this question because he supposes that there were any who did not desire life, or did not wish to see many days, but in order to fix the attention on the inquiry, and to prepare the mind for the answer which was to follow. By thus putting the question, also, he has implicitly expressed the opinion that it is lawful to desire life, and to wish to see many days.
And loveth many days - literally, “loving days.” That is, who so loves days, considered as a part of life, that he wishes they may be prolonged and multiplied.
That he may see good - That he may enjoy prosperity, or find happiness. In other words, who is he that would desire to understand the way by which life may be lengthened out to old age, and by which it may be made happy and prosperous? The psalmist proposes to answer this question - as he does in the following verses, by stating the results of what he had experienced and observed.