'Tribulation' in the Bible

For at that time there will be great tribulation, such as has not happened from the beginning of the world until now, nor ever will happen.

"And immediately after the tribulation of those days, 'the sun will be darkened and the moon will not give its light, and the stars will fall from heaven, and the powers of heaven will be shaken.'

For [in] those days there will be tribulation of such a kind as has not happened from the beginning of the creation that God created until now, and never will happen.

"But in those days, after that tribulation, 'the sun will be darkened and the moon will not give its light,

And I said to him, "My lord, you know." And he said to me, "These are the ones who have come out of the great tribulation, and have washed their robes and made them white in the blood of the Lamb.