Matthew 24:10-14 (New American Standard Bible)
10 And at that time many will fall away, and they will betray one another and hate one another. 11 And many false prophets will rise up and mislead many people. 12 And because lawlessness is increased, most people’s love will become cold. 13 But the one who endures to the end is the one who will be saved. 14 This gospel of the kingdom shall be preached in the whole world as a testimony to all the nations, and then the end will come.
So, in this scripture Matthew is looking forward towards End Times
He is talking about what will happen to the Christian Church: that it will disintegrate into treachery and hatred and that many members will be mislead by false prophets
So, it's going to be a trying time
But those who remain true will be saved - meaning they will not go to Hell, on account of being loyal to Jesus Christ
It then finishes on a more optimistic note, saying that the end will only come after all nations embrace the Gospel - which I can't imagine happening in the lifetime of most people who are alive today, but then of course if Jesus were to return tomorrow that would change everything
So, basically: For the church hard times are ahead. Its continued existence will be threatened from both outside and within. But those who stay true will remain saved, and everything will work out in the end.
That's what Matthew is saying in this scripture
What does this mean for Christians?
Stay true to Jesus (no matter what) and everything will work out in the end, both for you personally and for humankind as a whole