"We have been hearing since childhood that there is coolness and comfort in the remembrance of Allah." 

When we remember Allah or sit in the gathering of Allah, a cold wave runs through our body from the remembrance of Allah, has anyone ever noticed..?
Every short interval, suddenly a cold wave rushes rapidly into the spine, even in severe heat, such cold waves are felt, a cold wave, a wave that makes the hair stand on end, why are these cold waves felt? Because there is
coolness in the remembrance of Allah.
And it also happens that when we listen to a speech, Naat, poem, etc., we start feeling sleepy, and when we listen to dancing and singing, we are full of enthusiasm, then we do not feel sleepy because then we are restless. But we are understanding that these things are our peace. These things that seem to be our peace apparently, in fact, create restlessness, and those things that seem boring apparently, in fact, become the cause of peace.
When a person is restless, he cannot sleep, sleep is related to the satisfaction of the soul, the soul is satisfied with the remembrance of its creator.
When we offer prayers, remember Allah, or mention Him with His favorite servants, why do we feel sleepy...? Because there is
comfort in the remembrance of Allah.