The way I view this is complex.
Let's look at the Greek - what word is used for "man"?
Anthropos. generally in the New Testament, (besides two places because of presuppositions) Anthropos is a term for all of mankind, or specific people of mankind.
Paul uses the term for a singular man in this context, that is "tis".
The same is true in Revelation 13, the term used for "number of man (a is not in the Greek) is anthropos - 666 is the number of mankind
Who are those that are the men of lawlessness?
Those that reject Holiness. They are under the Jude 4 gospel, living a life of licentiousness under what they call "Grace".
With that build up let's answer the question with scripture:
Yes, that verse must be fulfilled before the return of the Lord, and as Jesus clearly says in Matt 24:29-31:
Matthew 24:29-31 NKJV - "Immediately after the tribulation of
those days the sun will be darkened, and the moon will not give its
light; the stars will fall from heaven, and the powers of the heavens
will be shaken. "Then the sign of the Son of Man will appear in
heaven, and then all the tribes of the earth will mourn, and they will
see the Son of Man coming on the clouds of heaven with power and great
glory. "And He will send His angels with a great sound of a trumpet,
and they will gather together His elect from the four winds, from one
end of heaven to the other.
The Dispensationalist, especially the hyper dispensationalist will tell us the words of Jesus don't apply to us today.
That's not what Paul believed.
1 Thessalonians 4:2 NKJV - for you know what commandments we gave you
through the Lord Jesus.
1 Timothy 6:3 NKJV - If anyone teaches otherwise and does not consent
to wholesome words, [even] the words of our Lord Jesus Christ, and to
the doctrine which accords with godliness,
So when could Christ return?
After the tribulation and after the men (plural) of lawlessness that are making vain sacrifices in Jesus' name are revealed.
Romans 12:1 NKJV - I beseech you therefore, brethren, by the mercies
of God, that you present your bodies a living sacrifice, holy,
acceptable to God, [which is] your reasonable service.
We are the temple of God, and when someone in SIN not living a holy and sanctified life claims to be a follower of Jesus, they are making the profane and lawless sacrifice. They have taken the mark of Cain, the mark of the Beast.
There is going to be a point (I have no idea when) - when who you are, is what you will be.
Revelation 22:11 NKJV - "He who is unjust, let him be unjust still; he
who is filthy, let him be filthy still; he who is righteous, let him
be righteous still; he who is holy, let him be holy still."
Hebrews 12:15-17 NKJV - looking carefully lest anyone fall short of
the grace of God; lest any root of bitterness springing up cause
trouble, and by this many become defiled; lest there [be] any
fornicator or profane person like Esau, who for one morsel of food
sold his birthright. For you know that afterward, when he wanted to
inherit the blessing, he was rejected, for he found no place for
repentance, though he sought it diligently with tears.
We need to make sure we're living a justified life in Christ - FREE of sin.
Galatians 2:17 NKJV - "But if, while we seek to be justified by
Christ, we ourselves also are found sinners, [is] Christ therefore a
minister of sin? Certainly not!
The Dispensationalists (from talking to them) believe this is a literal man who will rule the world, and everyone will bow to Him.
We already have people with the mark on their forehead, when they don't serve God they serve Satan. (Romans 6:16)
As God told the Jews, when we obey Him, we have the law on our mind (metapon) on our heart and manifest on our hands