The Khushoo’ of true faith is when the heart feels aware and humble before the greatness and glory of Allah, and is filled with awe, fear shyness, so that the heart is utterly humbled before Allah and is broken, as it were, with fear, shyness, love and the recognition of the blessings of Allah and its own sins. So no doubt the Khushoo’ of the heart is followed by the Khushoo’ of the body.
As for the Khushoo’ of hypocrisy, it is something that is put on with a great show, but there is no Khushoo’ in the heart. One of the Sahabah used to say,
“I seek refuge with Allah from the Khushu’ of hypocrisy.”It was said to him, “What is the Khushu’ of hypocrisy?” He said,
“When the body appears to have Khushu’ but there is no Khushoo' in the heart.”
The person who truly feels Khushoo’ before Allah is a person who no longer feels the flames of physical desire; his heart is pure and is filled with the light of the greatness of Allah. His own selfish desires have died because of the fear and awe which have filled his overflowing heart so that his physical faculties have calmed down, his heart has become dignified and feels secure in Allah, the remembrance of Him, and tranquility descends upon him from his Lord. So he becomes humbled (mukhbit) before Allah, and the one who is humble is the one who is assured.
The land that is “mukhbit” is land that is low-lying, in which water settles, so the heart that is “mukhbit” is humble and content, like a low-lying spot of land into which water flows and settles. The sign of this is that a person prostrates to his Lord out of respect and humility, and never raises his head until he meets Him.
The arrogant heart, on the other hand, is one that is content with its arrogance and raises its head up like an elevated portion of land in which water never settles.
This is the Khushu’ of true faith.
Source: Kitab Ar-Rooh, pg. 314.