The world was founded on loving-kindness. A testimony of this loving-kindness is prayer, the center pillar of the world. Thus, prayer lies at the heart of human existence, a crossing through which Man meets the Divine. A Divine gift, it has been imbedded into the nucleus of creation as a means for Man to plead for mercy.
Here are the words of the Ramban regarding the nature of prayer. “Prayer is an expression of G-d’s kindness to listen to all who call out to Him in prayer, just as a loving king, in his great mercy, listens to the requests of his people.”
But how does one begin to approach the infinite? How does one offer up praise to One who is beyond all praise? Chazal teach, “Where you find G-d’s greatness, there you find His humility.” Accordingly, G-d ‘lowers’ Himself from beyond the highest of Heavens to listen to Man’s requests, then fulfills them, as it is written, “It will be that before they (Yisrael) call, I will answer, while they yet speak (in prayer) I will hear (and grant their requests, and fulfill the desire of their hearts).
It is explained that without G-d’s permission it would be forbidden to approach Him with our requests. On the surface, the idea of Man suggesting to G-d what would be best is irrational. G-d, however, in His great humility listens to the requests of Man.
To praise G-d would also be forbidden without G-d’s permission, since any praise we would offer up will fall far short of representing His true greatness. G-d, however, out of His great kindness, ‘lowers’ Himself to our level of praise, considering it a merit rather than an insult.
A young boy reaches into his pocket to pay for a candy bar, but he’s lost his money. Donald, next in line, realizes what has happened. “Give him a few of those on me”, he says pointing to the candy bars. The boy turns to Donald, overjoyed at his display of kindness, and begins to thank him. “You must have a lot of money if you can afford to pay for so many candy bars; my father says that they're very expensive so I can only get one a week if I behave. Donald smiles and hands the cashier a crisp hundred dollar bill, which further amazes the boy who never saw a bill with so many zeros on it. What the boy didn’t realize is that Donald was in fact Donald Trump, and that he had walked into one of the stores located at the ground level of Trump Plaza across from the famous Manhattan Park.
 Perkei Avot 1:2; according to many commentators the reference to “service” refers to the daily service in the Beit Hamikdash. Today, however, it is represented by prayer, which was instituted in place of the daily service after the destruction of the Beit Hamikdash. One can also explain that the word “service” is a direct reference to prayer, which is also called “service”. See Sifri Parshat Ekev, Ta’anit 2a, where the Sages derive that the term “service of the heart” is a reference to prayer.
 Isaiah 65:24; and see commentary there.