Seeing his days are determined, the number of his months are with thee, thou hast appointed his bounds that he cannot pass;

Wesley's Notes

14:5 Determined - Limited to a certain period. With thee - In thy power and disposal. Thou hast appointed a certain end of his days, beyond which he cannot prolong his life.

Jamieson-Fausset-Brown Bible Commentary

5. determined-(Job 7:1; Isa 10:23; Da 9:27; 11:36).

Matthew Henry's Concise Commentary

14:1-6 Job enlarges upon the condition of man, addressing himself also to God. Every man of Adam's fallen race is short-lived. All his show of beauty, happiness, and splendour falls before the stroke of sickness or death, as the flower before the scythe; or passes away like the shadow. How is it possible for a man's conduct to be sinless, when his heart is by nature unclean? Here is a clear proof that Job understood and believed the doctrine of original sin. He seems to have intended it as a plea, why the Lord should not deal with him according to his own works, but according to His mercy and grace. It is determined, in the counsel and decree of God, how long we shall live. Our times are in his hands, the powers of nature act under him; in him we live and move. And it is very useful to reflect seriously on the shortness and uncertainty of human life, and the fading nature of all earthly enjoyments. But it is still more important to look at the cause, and remedy of these evils. Until we are born of the Spirit, no spiritually good thing dwells in us, or can proceed from us. Even the little good in the regenerate is defiled with sin. We should therefore humble ourselves before God, and cast ourselves wholly on the mercy of God, through our Divine Surety. We should daily seek the renewing of the Holy Ghost, and look to heaven as the only place of perfect holiness and happiness.