Mark 13:7

But when you hear of wars and rumors of wars do not be dismayed, such things must come, but the end is not yet.

Matthew 18:7

"Woe unto the world because of such stumbling-blocks! They will surely come, but woe unto each man by whom they come!

Matthew 24:6-7

And you will hear of wars and rumors of wars; see to it that you are not afraid. Such things must happen, but the end is not yet.

Luke 21:9-11

"And when you shall hear of wars and tumults, do not be frightened; for these things must happen first, but the end does not come immediately."

John 14:1

"Let not your hearts be troubled. You trust in God, trust in me also.

John 14:27

"Peace I leave with you. My own peace I give to you. It is not the world's 'Peace' I give you. Let not your heart be troubled, neither let it be afraid.

Acts 17:3

explaining and quoting passages to prove that the Messiah had to suffer and to rise again from the dead and that "This Jesus whom I am proclaiming unto you is the Messiah."

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 and rumors of wars; see to it that you are not afraid. Such things must happen, but the end is not yet.
Luke 21:9
"And when you shall hear of wars and tumults, do not be frightened; for these things must happen first, but the end does not come immediately."
John 14:1
"Let not your hearts be troubled. You trust in God, trust in me also.

Must

Matthew 18:7
"Woe unto the world because of such stumbling-blocks! They will surely come, but woe unto each man by whom they come!
Acts 17:3
explaining and quoting passages to prove that the Messiah had to suffer and to rise again from the dead and that "This Jesus whom I am proclaiming unto you is the Messiah."