St. Catherine of Siena

You must never turn back for anything at all. You must not break away from holy prayer for any reason except obedience or charity. For often during the time scheduled for prayer the devil comes with all sorts of struggles and annoyances - even more than when you are not at prayer. He does this to make you weary of holy prayer. Often he will say, 'This sort of prayer is worthless to you. You should not think about or pay attention to anything except vocal prayer.' He makes it seem this way so that you will become weary and confused, and abandon the exercise of prayer. But prayer is a weapon with which you can defend yourself against every enemy. If you hold it with love's hand and the arm of free choice, this weapon, with the light of most holy faith, will be your defense.