Qur'an 13: 28-29 in the remembrance of Allah hearts do find their tranquility -

But those who believe are over flowing in their love for Allah. Qur'an 2: 165.

When a Believer with an insight, practices contemplation - TAFAKKUR - "the root of understanding and motivation", everything within and around him points to One Entity as the Originator and Designer. And, to fall in over flowing Love with that ENTITY is natural. Heart having developed one on one base relationship of closeness and familiarity with the Creator, such heart does find contentment in silent, meditative FRIENDLY REMEMBRANCESof Allah within their own souls. The spiritual experiences and signs received internally cannot be shared with others, who have not received that light or that experience.

"Those who believe, and whose hearts find repose in the remembrance of Allah: for without doubt, in the remembrance of Allah hearts do find their tranquility - (and) they who attain faith and do righteous deeds are destined for blessedness (in this world) and the most beauteous of all goals (in the life to come)." Qur'an 13: 28-29.