99 When you go to pray, let this be a firm resolution: Don’t prolong your prayer just because you find consolation in it, nor curtail it just because you find it dry.
101 Persevere in prayer. Persevere, even when your efforts seem sterile. Prayer is always fruitful.
104 Pernoctans in oratione Dei—“He spent the whole night in prayer to God,” says Saint Luke of our Lord.
And you? How many times have you persevered like that?
—from The Way by Saint Josemaria Escriva