It is not necessary…

But it is not necessary for us to set forth our petitions before God in order to make known to him our needs or desires, but rather that we ourselves may realize that in these things it is needful to have recourse to the divine assistance.
–Saint Thomas Aquinas (1225-1274)

The purpose of…

The purpose of prayer is not to inform our Lord what you desire, for He knows all your needs. It is to render you able and ready to receive the grace which our Lord will freely give you. This grace cannot be experienced until you have been refined and purified by the fire of desire in devout prayer. For although prayer is not the cause for which our Lord gives grace, it is nevertheless the means by which grace, freely given, comes to the soul.
–Walter Hilton (1340-1396)

If you want, pray…

If you want faith, pray. If you want help, pray. If you want to love, pray. If you want poverty [of spirit], pray. If you want obedience, pray. If you want to charity, pray. If you want meekness, pray. If you want fortitude, pray. If you want any virtue, pray.
–Saint Angela of Foligno (1248-1309)

Mental prayer is…

Vicious tendencies are produced only by our corrupt nature, and it is very difficult to conquer them without mental prayer; but by means of this prayer we can overcome them easily. The soul in mental prayer is like iron in the fire: when the iron is cold, it is difficult to work; but when it is put into the fire, it becomes soft and allows itself to be easily worked: so it is with the soul… When a soul comes out from mental prayer it is quite changed.
–Saint Alphonsus Liguori (1696-1787)

The purpose of prayer…

The purpose of prayer is not to inform our Lord what you desire, for He knows all your needs. It is to render you able and ready to receive the grace which our Lord will freely give you. This grace cannot be experienced until you have been refined and purified by the fire of desire in devout prayer. For although prayer is not the cause for which our Lord gives grace, it is nevertheless the means by which grace, freely given, comes to the soul.
–Walter Hilton (1340-1396)