In the great tribulation, who shall be able to stand when the distress, the grievous times, and persecutions shall come? The Bible calls those times the great tribulations: "For then shall be great tribulation such as was not since the beginning of the world to this time, no, nor ever shall be" (Matthew 24:21).
John saw mountains and islands moving out of their places and people running and crying unto the mountains and rocks to fall on them to hide them from the wrath of the Lamb. John saw so much coming into the world, so he asked God in Revelation 6:17, "Who shall be able to stand?"
In Revelation 7:9, "John seen a multitude which no man could number, standing before the Lamb, clothed in white robes." In verse 13, one of the elders asked John, "Who are these in white robes, and where did they come from?" John said unto the elder in verse 14, "Sir, thou know. He said unto me, These, are they which came out of great tribulation, and have washed their robes and made them white in the blood of the Lamb." To make our robes white in the blood of the Lamb, we have got to do as it is written in Isaiah 1:18: "Come now, and let us reason together, saith the Lord: though your sins be as scarlet, they shall be as white as snow; thou they be red like crimson, they shall be as wool." Those shall be the ones who shall be able to stand.