Generally when people are “marked” in the Bible, it is for their protection, and Swedenborg offers a spiritual meaning which is similar: It means that what is good is distinguished from other things around it so that it can be preserved.
Obviously these don’t need to be physical marks – the Lord does not need to write notes on the backs of his hands to remember things. But when we think of receiving such a mark, or of certain good things in us being marked, it can help us on our spiritual journey.
Passages from Swedenborg
Arcana Coelestia (Elliott) n. 396
396. ‘Jehovah put a sign on Cain, lest anyone should strike him’ means that the Lord distinguished faith in a special way to ensure its preservation. This is clear from the meaning of ‘a sign’ and of ‘putting asign’ on somebody, which is a way of distinguishing him, as in Ezekiel,
Jehovah said, Go through the middle of the city, through the middle of Jerusalem, and make a sign on (or designate) the foreheads of the men (vir) who groan and sigh over all the abominations. Ezek. 9:4.
Here ‘designating foreheads’ does not mean putting a sign or stroke on their foreheads but a way of distinguishing from others. Something similar is said in John about men who did not have God’s sign on their foreheads being subject to condemnation, Rev. 9:4. Here again ‘having a sign’ stands for a way of distinguishing.
[2] In the same book this sign is also called ‘a mark’, where reference is made to placing a mark on the hand and on the forehead, Rev. 14:9. That which was meant by signs and marks the Jewish Church represented by binding the first and great commandment on to the hand and on to the forehead, a practice mentioned in Moses,
Hear, O Israel, Jehovah our God is one Jehovah; you shall love Jehovah your God, with all your heart, and with all your soul, and with all your might. And you shall bind them as a sign on to your hand; and let them be as frontlets between your eyes. Deut. 6:4, 5, 8; 11:13, 18.
This represented the requirement to distinguish the commandment concerning love above all other commandments. This shows what making a sign on the hand and on the forehead means.
In Isaiah,
One is coming to gather all nations and tongues, and they will come and see My glory, and I will set asign among them. Isa. 66:18, 19.
And in David,
Look to me and have compassion on me; give Your strength to Your servant, and save the son of Your handmaid. Make a sign in me for what is good, and let those who hate me see and be put to shame. Ps. 86:16, 17.
From all these quotations it is now clear what ‘a sign’ means. Let nobody suppose therefore that somesign was put on a man called Cain, for the internal sense of the Word embodies matters altogether different from those of the sense of the letter.
Apocalypse Explained (Tansley) n. 427
[2] That to be sealed does not mean to be sealed, but to be brought into that state in which their quality can be known, so that they may be conjoined with those who are in a similar state, and separated from those who are in a dissimilar state, is signified by being marked, and by a mark, in the following passages.
In Ezekiel:
“And Jehovah said,” to the man clothed in linen, “Go through the midst of the city, through the midst of Jerusalem, and set a mark upon the foreheads of the men that mourn and that sigh for all the abominations that be done in the midst thereof. Go ye through the city after him, and smite; let not your eye spare, neither have ye pity; but come not near any man upon whom is the mark” (ix. 4-6).
The subject is here the separation of the good from the evil. To be marked (or sealed) on the foreheadhas the same signification as in this passage in the Apocalypse, that is, to be distinguished and separated from the evil, and conjoined to the good. The casting-out of the evil, and their condemnation are also afterwards described. Those who are in good are described by the men that cry and sigh for all the abominations done in the midst of the city of Jerusalem. Those who mourn and sigh over the abominations are such as are not in evils and the falsities therefrom; mourning and sighing over them signify aversion and grief on account of them, Jerusalem denoting the church, and the city doctrine. The casting-out of the evil and their condemnation are afterwards described, by the command that they should go through the city after him and smite, and that their eye should not spare. To smite and to kill signify to be damned, for spiritual death is damnation, and is signified in the Word by natural death.
[3] In Isaiah:
“He will come to gather together all nations and tongues, that they may come and see my glory. And I will set a mark among them” (lxvi. 18, 19).
These words are spoken concerning the Lord, and the new church to be established by Him, and therefore concerning the new heaven and the new earth, as is evident from verse 22 of that chapter. By gathering together all nations and tongues, the same is signified as by gathering together the elect from the four winds (Matt. xxiv. 31). To gather together signifies to call His own to Himself; nations signify those who are in good, and tongues, those who are in a life according to doctrine. To come and see the glory of the Lord, signifies to be enlightened in Divine Truth, and thus to experience heavenly joy; for the glory of the Lord signifies the Divine Truth, and the illustration and joy which it affords. To set amark among them, signifies to distinguish and separate them from the evil, and conjoin them to the good.
Arcana Coelestia (Potts) n. 9936
[2] As the forehead with man corresponds to his love, therefore they who are in celestial love (that is, in love to the Lord from the Lord) are said to have “a mark on their foreheads,” by which is signified that they are under the Lord’s protection, because they are in His love, as in the following passages:
Jehovah said, Go through the midst of Jerusalem, and set a mark upon the foreheads of the men that groan and sigh for all the abominations that are done in the midst thereof; and smite; let not your eye spare; but come not near against any man upon whom is the mark (Ezek. 9:4-6).
Behold the Lamb standing on the Mount Zion, and with Him a hundred and forty and four thousand, having the name of His Father written on their foreheads (Rev. 14:1).
They shall see the faces of God and of the Lamb, and His name shall be on their foreheads (Rev. 22:4).
It was said that they should not hurt the grass of the earth, neither any green thing, nor any tree; but only the men that have not the mark of God on their foreheads (Rev. 9:4).
[3] “Having the mark,” or seal, “of God,” and “the name of God,” “on their foreheads,” denotes to be in safety from the infestation of evils which are from hell, because they are in the Lord through love; “the grass and the green thing,” which were not to be hurt, denote the memory-truth through which is the truth of faith (n. 7571, 7691); “the tree,” which also was not to be hurt, denotes the perception of truth from good (n. 103, 2163, 2722, 2972, 4552, 7692).