Genesis 4:15

And the Lord said unto him
In order to satisfy him, and make him easy in this respect, that: he need not fear an immediate or bodily death, which was showing him great clemency and lenity; or in answer to his begging for death, "therefore", or as some render the word, taking them for two, "not so" ^F25; it shall not be that whoever finds thee shall slay thee, thou needest not be afraid of that; nor shall thy request be granted, that thou mightest be slain by the first man that meets thee: it was the will of God, that though Cain deserved to die, yet that he should not die immediately, but live a long miserable life, that it might be a terror to others not to commit the like crime; though rather the particle should be rendered "verily, surely, of a truth" ^F26; so it will certainly be, it may be depended on:

whosoever slayeth Cain, vengeance shall be taken on him sevenfold;
seven times more than on Cain; that is, he shall be exceedingly punished; vengeance shall be taken on him in a very visible manner, to a very great degree; the Targums of Onkelos and Jonathan are

``unto or through seven generations;''

the meaning of which is, that the slayer of Cain should not only be punished in his own person, but in his posterity, even unto seven generations; and not as Jarchi and Aben Ezra interpret it, that God deferred his vengeance on Cain unto seven generations, and at the end of them took vengeance on him by Lamech, one of his own posterity, by whom he is supposed by that Jewish writer to be slain:

and the Lord set a mark upon Cain;
about which there is a variety of sentiments ^F1: some say it was a horn in his forehead: others, a leprosy in his face; others, a wild ghastly look; others, a shaking and trembling in all his limbs; and others, that there was an earthquake wherever he stepped: and others will have it, that the dog which guarded Abel's flock was given him to accompany him in his travels, by which sign it might be known that he was not to be attacked, or to direct him from taking any dangerous road: some say it was a letter imprinted on his forehead, either taken out of the great and glorious name of God, as the Targum of Jonathan, or out of his own name, as Jarchi; others the mark or sign of the covenant of circumcision ^F2: but as the word is often used for a sign or miracle, perhaps the better rendering and sense of the words may be, "and the Lord put", or "gave a sign" ^F3; that is, he wrought a miracle before him to assure him, that "whoever found him should not kill him": so that this was not a mark or sign to others, to direct or point out to them that they should not kill him, or to deter them from it; but was a sign or miracle confirming him in this, that no one should kill him; agreeably to which is the note of Aben Ezra,

``it is right in my eyes that God made a sign (or wrought a miracle) for him, until he believed;''