And thy life shall hang in doubt before thee; and thou shalt fear day and night, and shalt have none assurance of thy life:

Wesley's Notes

28:66 Thy life shall hang in doubt - Either because thou art in the hands of thy enemies that have power, and want no will, to destroy thee: or because of the terrors of thy own mind, and the guilt of thy conscience making thee to fear, even where no fear is.

Matthew Henry's Concise Commentary

28:45-68 If God inflicts vengeance, what miseries his curse can bring upon mankind, even in this present world! Yet these are but the beginning of sorrows to those under the curse of God. What then will be the misery of that world where their worm dieth not, and their fire is not quenched! Observe what is here said of the wrath of God, which should come and remain upon the Israelites for their sins. It is amazing to think that a people so long the favourites of Heaven, should be so cast off; and yet that a people so scattered in all nations should be kept distinct, and not mixed with others. If they would not serve God with cheerfulness, they should be compelled to serve their enemies. We may justly expect from God, that if we do not fear his fearful name, we shall feel his fearful plagues; for one way or other God will be feared. The destruction threatened is described. They have, indeed, been plucked from off the land, ver. 63. Not only by the Babylonish captivity, and when Jerusalem was destroyed by the Romans; but afterwards, when they were forbidden to set foot in Jerusalem. They should have no rest; no rest of body, ver. 65, but be continually on the remove, either in hope of gain, or fear of persecution. No rest of the mind, which is much worse. They have been banished from city to city, from country to country; recalled, and banished again. These events, compared with the favour shown to Israel in ancient times, and with the prophecies about them, should not only excite astonishment, but turn unto us for a testimony, assuring us of the truth of Scripture. And when the other prophecies of their conversion to Christ shall come to pass, the whole will be a sign and a wonder to all the nations of the earth, and the forerunner of a general spread of true christianity. The fulfilling of these prophecies upon the Jewish nation, delivered more than three thousand years ago, shows that Moses spake by the Spirit of God; who not only foresees the ruin of sinners, but warns of it, that they may prevent it by a true and timely repentance, or else be left without excuse. And let us be thankful that Christ hath redeemed us from the curse of the law, by being made a curse for us, and bearing in his own person all that punishment which our sins merit, and which we must otherwise have endured for ever. To this Refuge and salvation let sinners flee; therein let believers rejoice, and serve their reconciled God with gladness of heart, for the abundance of his spiritual blessings.