The hidden ones are the chosen remnant of Israel. Every spirit filled christian who stands firm until the end. God promises to hold them in peace and safety from the dangers of the enemy and from the troubles of the world. Hidden deep within God's secret pavillion and under the shadow of his wings. Note that this doesn't necessarily exclude a Christian from pain and suffering, but rather, God now metes out that suffering in order to refine us in fire like pure gold, whereas before, our suffering was not a godly suffering

Romans 5:3-4 Not only that, but we rejoice in our sufferings, knowing that suffering produces endurance, and endurance produces character, and character produces hope.

Psalms 31:20 Thou shalt hide them in the secret of thy presence from the pride of man: thou shalt keep them secretly in a pavilion from the strife of tongues.

Psalms 32:7 Thou art my hiding place; thou shalt preserve me from trouble; thou shalt compass me about with songs of deliverance. Selah.

Isaiah 4:5 And the Lord will create upon every dwelling place of mount Zion, and upon her assemblies, a cloud and smoke by day, and the shining of a flaming fire by night: for upon all the glory shall be a defence. 6 And there shall be a tabernacle for a shadow in the day time from the heat, and for a place of refuge, and for a covert from storm and from rain.

Those who dwell in the safety of the most high are called Christians. Cloud and smoke and a pillar of fire is the covering of the holy spirit.