David' prayer (1 Chronicles 29, 10-18)
Therefore David blessed the Lord in the presence of all the assembly; and David said: "Blessed art thou, O Lord, the God of Israel our father, for ever and ever. Thine, O Lord, is the greatness, and the power, and the glory, and the victory, and the majesty; for all that is in the heavens and in the earth is thine; thine is the kingdom, O Lord, and thou art exalted as head above all.
Both riches and honor come from thee, and thou rulest over all. In thy hand are power and might; and in thy hand it is to make great and to give strength to all. And now we thank thee, our God, and praise thy glorious name. "But who am I, and what is my people, that we should be able thus to offer willingly? For all things come from thee, and of thy own have we given thee [...]
God listens to us and fulfills our prayers, if it is for our good (1 John 5,14-15)
And this is the confidence which we have in him, that if we ask anything according to his will he hears us. And if we know that he hears us in whatever we ask, we know that we have obtained the requests made of him.
God wants to give us of good things (Matthew 7,7-11)
Ask, and it will be given you; seek, and you will find; knock, and it will be opened to you. For every one who asks receives, and he who seeks finds, and to him who knocks it will be opened. Or what man of you, if his son asks him for bread, will give him a stone? Or if he asks for a fish, will give him a serpent? If you then, who are evil, know how to give good gifts to your children, how much more will your Father who is in heaven give good things to those who ask him!
The importance of the prayer for some (Matthew 18,19-20).
Again I say to you, if two of you agree on earth about anything they ask, it will be done for them by my Father in heaven. For where two or three are gathered in my name, there am I in the midst of them".