People who came to faith during the Trib who refused to take the MotB.
Who is being martyred in Revelation 6:9-11
In Matthew 24, Jesus is answering three questions:
As He was sitting on the Mount of Olives, the disciples came to Him privately, saying, "Tell us, when will these things happen, and what will be the sign of Your coming, and of the end of the age?"
The verse you asked about, Matthew 24:9 , is in the 'when will these things happen' part.
And Jesus answered and said to them, "See to it that no one misleads you. "For many will come in My name, saying, 'I am the Christ,' and will mislead many. "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 because of My name. "At that time many will fall away and will betray one another and hate one another. "Many false prophets will arise and will mislead many. "Because lawlessness is increased, most people's love will grow cold.
You also need to keep in mind that the focus here (in the Gospels, and Matthew in particular) is still on the Jewish people, as are the events in the Trib.