Great tribulation (Matthew 24:21), Antichrist (1 John 2:18), Six hundred threescore and six (Revelation 13:18), Mark of the beast (Revelation 16:2) are words that bring fear and fearfulness into untold numbers of people.
There is no reason to fear because we trust in GOD.
“Be still, and know that I am God: I will be exalted among the heathen, I will be exalted in the earth. The LORD of hosts is with us; the God of Jacob is our refuge. Selah” (Psalm 46:10-11).
“The fear of man bringeth a snare: but whoso putteth his trust in the LORD shall be safe” (Proverbs 29:25).
“It is a fearful thing to fall into the hands of the living God” (Hebrews 11:31).
“Cast not away therefore your confidence, which hath great recompence of reward. For ye have need of patience, that, after ye have done the will of God, ye might receive the promise. For yet a little while, and he that shall come will come, and will not tarry” (Hebrews 11:35-37).