Shaykh Al-ʿAllāmah Imām Rabīʿ bn Hādī ʿUmayr Al-Madkhalī حفظه الله ورعاه said:
“The servant should fear Allāh! By Allāh, these limbs will bear witness!
A man should not think that he has no watcher over him when he’s alone.
Your limbs, by Allāh, are watching over you; Allāh is great!
Therefore, a servant should take account of himself, wherever he is, that is—in public and in private.
And It is more important to fear Allāh, the Almighty, in private, because the true believing servant in his solitude; shows in his faith, his piety and his tears, due to the fear of Allāh—what he does not show in front of people.
And this is from those who fall into the seven whom Allāh will shade under his shade:
“And a man who remembers Allāh in private, till his eyes are overflowed with tears.”
The miscreant hypocrite, when in solitude; wrongs, oppresses, violates and breaches the sanctities of Allāh.
And the true believer while in solitude, is better than when he mixes with people.
So be like that, oh brothers!
May Allāh grant us success and you, and protect us from hypocrisy – Allāh’s refuge is sought – and from pretending to be good and hiding evil.”
Kitāb Adh-Dharī ʿah (2/570-571).