Perfect love casts out fear.

1 John 4:18 KJV

[18] There is no fear in love; but perfect love casteth out fear: because fear hath torment. He that feareth is not made perfect in love.

Fear that causes torment is the kind of fear you have when you are in danger. The fear of God that causes torment comes when you are in danger of His painful discipline, because you are sinning. Perfect love casts out this kind of fear.

John 14:21A KJV

[21] He who has My commandments and keeps them, it is he who loves Me.

Perfect love involves keeping God‘s commandments. Keeping God’s commandments keeps you away from the danger of His discipline. And so casts out the tormenting fear of being in this danger.

Instead, you have the fear of God that keeps you far away from His chastening. Chastening brought on by disobeying Him. This sort of fear does not torment. Instead, it comforts.