Says Allah Ta'ala in ayat 28 of Surat Ra'ad of the Holy Qur'an:--
"Verily, in the remembrance of Allah do hearts find rest/satisfaction." (13:28)
And in Hadith, we have learnt it that the Prophet, Sallallahu alaihi Wasallam, said:-
"There is a piece of flesh in the body, if it becomes good (reformed), the whole
body becomes good but if it gets spoiled, the whole body gets spoiled and that
is the heart."
Sheikh Abu Abdullah at-Tirmidhi Hakeem, may Allah be Merciful to him, said:--
"The Zikr [Remembrance ] of Allah moistens the heart and cultivates tenderness in it.
When the heart is bereft of Zikrullah, the heat of the nafs overtakes it; the fire
of lust reaches it; and it becomes barren and hard."
Indeed, the life of the heart (qalb) is related to Allah's Remembrance. Man has only to implant Allah's Name firmly in his heart, what follows is amazing. So, be engaged in Zikr always... or most of the time. With that, you find out that even though our hands cannot feel Allah Ta'ala, the mind cannot grasp Him but the heart would vividly recognize Him... Tabaraka Wa Ta'ala.
With regular, constant Zikr, the heart can discern Allah, Jallah-Jalalahu, hear Him, entreat, Obey and act according to His Will.