Why is a man subject to more temptations when he prays to God than at ordinary times?

Blessed Giles of Assisi:

“When a man has a case to defend at the prince’s court against his adversary, if he goes to the prince to present his case and obtain justice against the adversary, the latter, informed of his efforts, does everything possible so that the judgment may not be favorable to him.

So the devil acts toward us. If, therefore, you spend your time conversing with others, you will often find that you do not have to endure many temptations. But if you turn to prayer in order to draw strength for your soul, then you will feel against you the most burning darts of the enemy.

You must not for that reason abandon prayer, but persevere in it resolutely, because it is the road to the heavenly homeland. Whoever would abandon prayer at that moment would be like the soldier who takes flight in the midst of battle.”