According to 4:3, Would those who believe Jesus is still to come 'in the flesh' again; [other than the continual generational indwelling of believers] be among those who are of the opposed [anti-] the principles and truths of Christ established at his coming?
As for a single personage or personages of 'anti-Christ', or anti-Messiah it would seem that it and they would have occurred during the time for which the Messiah had been prophesied to come. This was during the first century. And there is many who proclaimed to be Christ and who were put to death by the Romans. These are who John is talking about in 2:18.
And there is finally Simon bar Kochbah of @ 130 AD who was presented by the reformed Sanhedrain as "Messiah" during the attempted restoration of 'Israel" of that time. They appealed to the prophecy of Numbers 24:17-19 and realized that this was a prophecy for Messiah and that the time had come for the fulfillment of that prophecy. They fabricated and changed a mans name to refer to a 'star' in order to attempt to fulfill the prophecy and further reject it's fulfillment in Christ, the apostles and disciples.
Numbers 24:17 I shall see him, but not now: I shall behold him, but not nigh: there shall come a Star out of Jacob, and a Sceptre shall rise out of Israel, and shall smite the corners of Moab, and destroy all the children of Sheth.
18 And Edom shall be a possession, Seir also shall be a possession for his enemies; and Israel [Christians] shall do valiantly.
19 Out of Jacob shall come he that shall have dominion, [Dan 7:13, 14; 26,27] and shall destroy him that remaineth of the city.
None of these verses by John indicate some future figure; but refer to those that reject his past visitation, indwelling and completed coming.
17 Love has been perfected among us in this:
that we may have boldness in the day of judgment; because as He is, so are we in this world.
1 John 4:17
and again -
But the heavens and the earth which are now preserved by the same word,
are reserved for fire until the day of judgment and perdition of ungodly men.
2 Peter 3:7
and again -
5 But in accordance with your hardness and your impenitent heart you are treasuring up for yourself wrath
in the day of wrath and revelation of the righteous judgment of God, 6 who "will render to each one according to his deeds": 7 eternal life to those who by patient continuance in doing good seek for glory, honor, and immortality; 8 but to those who are self-seeking and do not obey the truth, but obey unrighteousness--indignation and wrath, 9 tribulation and anguish, on every soul of man who does evil, of the Jew first and also of the Greek; 10 but glory, honor, and peace to everyone who works what is good, to the Jew first and also to the Greek. 11 For there is no partiality with God. 12 For as many as have sinned without law will also perish without law, and as many as have sinned in the law will be judged by the law 13 (for not the hearers of the law are just in the sight of God, but the doers of the law will be justified; 14 for when Gentiles, who do not have the law, by nature do the things in the law, these, although not having the law, are a law to themselves, 15 who show the work of the law written in their hearts, their conscience also bearing witness, and between themselves their thoughts accusing or else excusing them) 16
in the day when God will judge the secrets of men by Jesus Christ, according to my gospel.
That Day, Known as the Day of the Lord has not come, for when it does, ALL will know that Jesus Christ is Lord, as it is written -
9
It shall be in that day that I will seek to destroy all the nations that come against Jerusalem. 10 "And I will pour on the house of David and on the inhabitants of Jerusalem the Spirit of grace and supplication;
then they will look on Me whom they pierced. Yes, they will mourn for Him as one mourns for his only son, and grieve for Him as one grieves for a firstborn.
Zechariah 12:9-10
Unfortunately for those
who claim this event came in 70 AD, they have trouble explaining as why Titus and the Romans were not destroyed according to the Word of the Lord -
I will seek to destroy all the nations that come against Jerusalem.
For you yourselves know perfectly that
the day of the Lord so comes as a thief in the night. 3 For when
they say,
"Peace and safety!" then sudden destruction comes upon them, as labor pains upon a pregnant woman. And they shall not escape. 4
But you, brethren, are not in darkness, so that this Day should overtake you as a thief.
JLB
