16 And they said to the mountains and to the rocks, “Fall on us and hide us from the face of the One seated on the throne and from the wrath of the Lamb,

All of the wicked people who worshiped idols, self, practiced witchcraft, denied the existence of God, now wants to hide from Jesus Christ’s judgment.

They wanted to be covered by the mountains but the mountains had no refuge for them because justice will be delivered.

17 because the great day of Their wrath has come! And who is able to stand?”

Everyone knows that they are guilty of sin because the Holy Spirit has made it evident to them but they love physical pleasures, what satisfies the flesh like riches, women, fame, power, love of self, and greed rather than Jesus Christ who gave up His life for them.

The phrase “And who is able to stand?” refers to being guiltless or asking the question of whos sins has been washed away by the blood of Jesus? The word “stand” means declared righteous as seen in  Jude 1:24 which says, “Now to Him who is able to protect you from stumbling and to make you stand in the presence of His glory, blameless and with great joy”