Yechezk'el 9:5-6 As I listened, he said to the others, "Follow him through the city and kill, without showing pity or compassion. Slaughter old men, young men and maidens, women and children, but do not touch anyone who has the mark. Begin at my sanctuary." So they began with the elders who were in front of the temple.
Yeshua gives out the judgment. Judgment begins with those who are more responsible. Judgment begins also with the household of G-d today. G-d chastises those whom He loves.
1 Peter 4:14-19 If you are reviled for the name of Messiah, you are blessed, because the Spirit of glory and of G-d rests upon you. By no means let any of you suffer as a murderer, or thief, or evildoer, or a troublesome meddler; but if anyone suffers as a believer, let him not feel ashamed, but in that name let him glorify G-d. For it is time for judgment to begin with the household of G-d; and if it begins with us first, what will be the outcome for those who do not obey the good news of G-d? And if it is with difficulty that the righteous is saved, what will become of the godless man and the sinner? Therefore, let those also who suffer according to the will of G-d entrust their souls to a faithful Creator in doing what is right.
In the future, those that will be slaughtered will be those that do not take the image or mark of the beast. The second beast, also know as the false prophet, will slaughter them.
Revelation 13:15-16 And there was given to him to give breath to the image of the beast, that the image of the beast might even speak and cause as many as do not worship the image of the beast to be killed.
Yechezk'el 9:7-10 Then he said to them, "Defile the temple and fill the courts with the slain. Go!" So they went out and began killing throughout the city. While they were killing and I was left alone, I fell facedown, crying out, "Ah, Sovereign L-RD! Are you going to destroy the entire remnant of Israel in this outpouring of your wrath on Yerushalayim (Jerusalem)?" He answered me, "The sin of the house of Israel and Y'hudah (Judah) is exceedingly great; the land is full of bloodshed and the city is full of injustice. They say, `The L-RD has forsaken the land; the L-RD does not see.' So I will not look on them with pity or spare them, but I will bring down on their own heads what they have done."
Yechezk'el is in anguish as he sees the wrath of the L-rd being carried out against the wicked. HaShem tells Yechezk'el that it is necessary to punish the wicked.
Yechezk'el 9:11 Then the man in linen with the writing kit at his side brought back word, saying, "I have done as you commanded."
In the future, during the time of Ya'akov's trouble, the temple will be defiled and many will be allowed to be slain by the serpent of old. A remnant will physically survive.
Mattityahu (Matthew) 24:4-28 "See to it that no one misleads you. "For many will come in My name, saying, 'I am the Messiah,' and will mislead many. "And you will be hearing of wars and rumors of wars; see that you are not frightened, for those things must take place, but that is not yet the end. "For nation will rise against nation, and kingdom against kingdom, and in various places there will be famines and earthquakes. "But all these things are merely the beginning of birth pangs. "Then they will deliver you to tribulation, and will kill you, and you will be hated by all nations on account of My name. "And at that time many will fall away and will deliver up one another and hate one another. "And many false prophets will arise, and will mislead many. "And because lawlessness is increased, most people's love will grow cold. "But the one who endures to the end, he shall be saved. "And this good news of the kingdom shall be preached in the whole world for a witness to all the nations, and then the end shall come. "Therefore when you see the abomination of desolation which was spoken of through Daniel the prophet, standing in the holy place (let the reader understand), then let those who are in Judea flee to the mountains; let him who is on the housetop not go down to get the things out that are in his house; and let him who is in the field not turn back to get his cloak. "But woe to those who are with child and to those who nurse babes in those days! "But pray that your flight may not be in the winter, or on a Sabbath; for then there will be a great tribulation, such as has not occurred since the beginning of the world until now, or ever will be. "And unless those days had been cut short, no life would have been saved; but for the sake of the elect those days shall be cut short. "Then if anyone says to you, 'Look, here is the Messiah,' or 'There He is,' do not believe him. "For false Messiah's and false prophets will arise and will show great signs and wonders, so as to mislead, if possible, even the elect. "LOOK, I have told you in advance. "If therefore they say to you, 'Look, He is in the wilderness,' do not go forth, or, 'Look, He is in the inner rooms,' do not believe them. "For just as the lightning comes from the east, and flashes even to the west, so shall the coming of the Son of Man be. "Wherever the corpse is, there the vultures will gather.