Mark 13:7

And when you hear of wars [going on] and rumors of [other] wars [pending], do not worry, for such things must necessarily happen. But the end has not yet come. [Note: By "end" here Jesus probably alludes to the downfall of Jerusalem in AD 70, with its attending destruction of the Temple buildings].

Matthew 18:7

"It will be too bad for the world because of occasions that cause people to fall away [from God]! For it is inevitable that such occasions come, but it is too bad for that person who is responsible for causing it to happen.

Matthew 24:6-7

And you will hear of wars [going on] and rumors of [other] wars [pending]. Do not worry, for such things must necessarily happen. But the end has not yet come. [Note: By "the end" here Jesus probably alludes to the downfall of Jerusalem, in AD 70, with its attending destruction of the Temple buildings].

Luke 21:9-11

And when you hear of wars and uprisings [going on], do not be afraid, for such things must necessarily happen first. But the end will not come right away." [Note: By "the end" here Jesus probably alludes to the downfall of Jerusalem, in AD 70, with its attending destruction of the Temple buildings].

John 14:1

[Jesus continued], "Do not allow your hearts to be upset. You should believe in God, and believe in me also.

John 14:27

I leave you with peace; I give you my peace. I am not giving you peace like the world gives. Do not allow your hearts to be upset or afraid.

Acts 17:3

explaining and declaring that it was necessary for Christ to suffer and [then] rise again from the dead. Paul was saying, "This Jesus, whom I am proclaiming to you, is the Christ."

Treasury of Scripture Knowledge

Summary

And when ye shall hear of wars and rumours of wars, be ye not troubled: for such things must needs be; but the end shall not be yet.

Bible References

When

Matthew 24:6
And you will hear of wars [going on] and rumors of [other] wars [pending]. Do not worry, for such things must necessarily happen. But the end has not yet come. [Note: By "the end" here Jesus probably alludes to the downfall of Jerusalem, in AD 70, with its attending destruction of the Temple buildings].
Luke 21:9
And when you hear of wars and uprisings [going on], do not be afraid, for such things must necessarily happen first. But the end will not come right away." [Note: By "the end" here Jesus probably alludes to the downfall of Jerusalem, in AD 70, with its attending destruction of the Temple buildings].
John 14:1
[Jesus continued], "Do not allow your hearts to be upset. You should believe in God, and believe in me also.

Must

Matthew 18:7
"It will be too bad for the world because of occasions that cause people to fall away [from God]! For it is inevitable that such occasions come, but it is too bad for that person who is responsible for causing it to happen.
Acts 17:3
explaining and declaring that it was necessary for Christ to suffer and [then] rise again from the dead. Paul was saying, "This Jesus, whom I am proclaiming to you, is the Christ."