Supplication is the heart and soul of worship because it is the reason behind creating a human being and its aim is to be attracted to God. Supplication achieves this attraction and connection to God through the widest ways and the strongest means.
It was narrated that the Prophet Mohammad (pbuh) said” resort to God Him to ask for your needs, fall back to Him in your misfortunes, beg Him, and call upon Him for supplication is the brain of worship, and there is no believer who calls upon God but He responds; Either he will hasten it for him in this world, or he will postpone it in the Hereafter, or he will atone for his sins as much as he prayed; As long as he is not called for a sin”.
The story almost shows us the way man moves to God through supplication and turns to Him.
(Resort to God to ask for your needs), (fall back to Him in your misfortunes), and (beg Him).
In another narration for the Prophet Mohammad (pbuh): “Supplication is the believer’s weapon and the support of religion”. 
Supplication is “the support of religion” because it is the backbone of religion and the movement of a human being towards God; supplication is approaching God.
Then, because the truth of supplication is approaching God, supplication is the best and most valuable behavior in the eyes of God.
The Prophet Mohammad (pbuh) said:” There is nothing more valuable to God almighty than supplication”. 
Narrated by Hannan bin Sadir, narrated by his father, he said:” I asked Al Imam Baker (pbuh) about the best worship, so he said that the best behavior in the eyes of God is to be asked for his blessings, and the best in His eyes is to avoid His worship and not to ask Him for his needs”.
God almighty says: (Call upon Me, I will answer you; surely those who are too proud for My service shall soon enter hell abased). 
What is meant in the verse about being too proud is the avoidance of supplication because the context encourages supplication. God almighty says:” Call upon Me, I will answer you”. Directly after that he says: (surely those who are too proud for My service shall soon enter hell abased).
Then avoidance of supplication in the noble verse means being too proud for God’s service; it is avoidance of God.
In the same context, Al Imam Al Sadek said explaining this verse:” I swear its worship, I swear its worship”.
Narrated by Hammad bin Issa, Al Imam Al Sadek (pbuh) said:” Supplication is the worship; God almighty says: (those who are too proud of My service shall soon enter hell abased). 
There is no value for a human being without supplication and its level. God only pays attention to his servant because of his supplication and approach to God (My Lord pays attention to you only because of your invocation to Him.)
That’s because supplication in reality is equivalent to approaching God, same as avoidance of supplication is avoidance of God; those who avoid God, He in return will not pay attention to him, and are invaluable in the eyes of God.
Narrated by Abu Jaafar Al Baker:” The most unpleasant by God is the one who is too proud to worship Him, and doesn’t ask God for His blessing”. 
The Prophet Mohammad said:” “You will ask God, or He will be angry with you. God has servants who work, and He gives them deserving. They ask Him truthfully, and He gives them, then He gathers them in Paradise, and those who worked will say: Our God, we have worked, so You gave us, so what did You give these? He says: These are My servants, I have given you your wages, and I have not deprived you of any of your deeds.. 
His Eminence Sheikh Muhammad Mahdi Al-Asifi, Conducted from “Supplication for the Ahl al-Bayt (peace be upon them)”
 Bihar Al Anwar 93 : .. 3.
 Bihar Al Anwar 93 : 2. 3.
 Bihar Al Anwar 93 : 288.
 Makarem Al Akhlaq: 311.
 Makarem Al Akhlaq: 311, and the same content in Al mahasin Al Barqi: 292
 Surah Ghafir: 60
 Al Shi’a Means 4 : 1083.
 Al Forqan: 77
 Al Shi’a Means 4 : 108 ? story no 8604.
 () Al Shi’a Means 4 : 1084 ? story no 8609.