And the Lord slew him. We know that long life is reckoned among the gifts of God; and justly: for since it is by no means a despicable honor that we are created after the image of God, the longer any one lives in the world, and daily experiences God's care over him, it is certain that he is the more bountifully dealt with by the Lord. Even amidst the many miseries with which life is filled, this divine goodness still shines forth, that God invites us to himself, and exercises us in the knowledge of himself; while at the same time he adorns us with such dignity, that he subjects to our authority whatever is in the world. Wherefore it is no wonder that God, as an act of kindness, prolongs the life of man. Whence it follows, that when the wicked are taken away by a premature death, a punishment for their wickedness is inflicted upon them: for it is as if the Lord should pronounce judgment from heaven, that they are unworthy to be sustained by the earth, unworthy to enjoy the common light of heaven. Let us therefore learn, as long as God keeps us in the world, to meditate on his benefits, to the end that every one may the more cheerfully endeavor to give praise to God for the life received from him. And although, at the present day also, sudden death is to be reckoned among the scourges of God; since that doctrine is always true, "Bloody and deceitful men shall not live out half their days," (Psalm 55:23;) yet God executed this judgment more fully under the law, when the knowledge of a future life was comparatively obscure; for now, since the resurrection is clearly manifested to us in Christ, it is not right that death should be so greatly dreaded. And this difference between us and the ancient people of God is elsewhere noted. Nevertheless, it can never be laid down as a general rule, that they who had a long life were thereby proved to be pleasing and acceptable to the Lord, whereas God has sometimes lengthened the life of reprobates, in aggravation of their punishment. We know that Cain survived his brother Abel many centuries. But as God does not always, and to all persons, cause his temporal benefits manifestly to flow in a perpetual and equable course; so neither, on the other hand, does he always execute temporal punishments by the same rule. It is enough that, as far as the present life is concerned, certain examples of punishments and rewards are set before us. Moreover, as the miseries of the present life, which spring from the corruption of nature, do not extinguish the first and special grace of God; so, on the other hand, death, which is in itself the curse of God, is so far from doing any injury, that it tends, by a supernatural remedy, to the salvation of the elect. Especially now, from the time that the first-fruits of the resurrection in Christ have been offered, the condition of those who are quickly taken out of life is in no way deteriorated; because Christ himself is gain both for life and death. But the vengeance of God was so clear and remarkable in the death of Er, that the earth might plainly appear to have been purged as from its filthiness.

Er - was wicked in the sight of the Lord - What this wickedness consisted in we are not told; but the phrase sight of the Lord being added, proves that it was some very great evil. It is worthy of remark that the Hebrew word used to express Er's wickedness is his own name, the letters reversed. Er ער wicked, רע ra. As if the inspired writer had said, "Er was altogether wicked, a completely abandoned character."

And Er, Judah's firstborn, was wicked in the sight of the Lord,.... That is, exceedingly wicked, as this phrase signifies, Genesis 13:13, was guilty of some very heinous sin, but what is not mentioned; according to the Targum of Jonathan and Jarchi, it was the same with his brother Onan's, Genesis 38:9, which it is suggested he committed, lest his wife should prove with child, and lose her beauty; but if it had been the same with his, it would have been expressed as well as his. An Arabic writer (p) says, that he cohabited with his wife not according to the course of nature, but in the "sodomitical" way:
and the Lord slew him; by his immediate hand, striking him dead at once, as Ananias and Sapphira were stricken, Acts 5:5; or by sending some distemper, which quickly carried him off, as a token of his displeasure at his sin.
(p) Abulpharag. Hist. Dynast. p. 16.

And Er was wicked in the sight of the Lord - That is, in defiance of God and his law. And what came of it? Why God cut him off presently, The Lord slew him. The next brother Onan was, according to the ancient usage, married to the widow, to preserve the name of his deceased brother that died childless. This custom of marrying the brother's widow was afterward made one of the laws of Moses, Deuteronomy 25:5. Onan, though he consented to marry the widow, yet to the great abuse of his own body, of the wife he had married, and the memory of his brother that was gone, he refused to raise up seed unto his brother. Those sins that dishonour the body are very displeasing to God, and the evidence of vile actions. Observe, the thing which he did displeased the Lord - And it is to be feared, thousands, especially of single persons, by this very thing, still displeased the Lord, and destroy their own souls.