The Complete Manual of Catholic Piety / Containing a Selection of Fervent Prayers, Pious Reflection, and Solid Instructions, Adapted to Every State of Life. To Which is Annexed a Supplement, Containing Excellent and Approved Devotions, With the Epistles and Gospels for All the Sundays and Festivals of the Year.

Of all the means we can employ for our advancement in the great affair of our salvation, Prayer is certainly one of the most powerful. Saint Augustin calls it the Key of Heaven, that unlocks the treasures of God, and gives us free access to the riches of his divine bounty. It was by prayer that Elias, when he pleased, opened and shut the sluices of heaven, and caused fire to descend from above to consume his sacrifice. It was by prayer that Joshua caused the sun to stop in the midst of its course. The prayer of Moses contributed more to the signal victory obtained by Joshua over the army of the Amalekites, than all the weapons of Israel: for as long as his hands were raised up to heaven, his prayers drew down a blessing on the people of God: but no sooner did he let his hands fall, (being unable to keep them in that painful posture,) and had ceased from prayer, than the Amalekites began to prevail.
But if Prayer be so powerful, it is no less necessary: our poverty and indigence; our manifold wants, infirmities, and miseries; the various dangers to which we are continually exposed; the frequent temptations we have to encounter; our absolute insufficiency of ourselves, and inability to do the least good without the grace of God; are corroborating proofs of the indispensable necessity of Prayer.

Though every good gift comes from the Father of Lights, who knows our wants, and is always inclined to relieve us, yet he requires that we have recourse in all our necessities, corporal and spiritual, to the throne of his mercy, under the assurance that whatever we ask with confidence, humility, piety, and perseverance, in the name of Jesus, shall be granted.
However, the idea of Prayer is not to be confined to that of Petition, as frequently happens. Many Christians, indeed, pray to God; but where are they to be found, who, like David, are incessantly employed in singing the mercies of the Lord, and have the remembrance of them deeply engraven in their hearts? They call upon God, to represent to him their wants, either temporal or spiritual; they appear only in his presence with a hand lifted up to receive, as if they imagined he was indebted to them, and that he never gave them enough. They have a heart but to wish, and a tongue but to ask. Their wants are eloquent and pressing, their gratitude cold and silent; for how seldom do they think of appearing before him to bless and praise him, and to celebrate the wonders of his love for us! Alas! to recollect his benefits, to thank him for them, to feel confused at the sight of their own ingratitude, to excite themselves, from this motive, to confidence and love, to be ready to do all, to suffer all, for a God who has shown them so much goodness, is a practice which is known but to a small number of fervent souls. We are all earnest in asking; but in general so deficient in thanksgiving, that, like the Lepers in the Gospel, it is to be feared not above one in ten gives due thanks to God for the blessings received.