Faith is not merely a personal reaching out towards things to come that are still totally absent: it gives us something. It gives us even now something of the reality we are waiting for, and this present reality constitutes for us a “proof” of the things that are still unseen. Faith draws the future into the present, so that it is no longer simply a “not yet”. The fact that this future exists changes the present; the present is touched by the future reality, and thus the things of the future spill over into those of the present and those of the present into those of the future – Spe Salvi.

When You Have An Evil Thought, Do This! | St. Alphonsus Liguori
"When an evil thought is presented to the mind, we must immediately endeavor to turn our thoughts to God, or to something which is indifferent. But the first rule is, instantly to invoke the names of Jesus and Mary and to continue to invoke them until the temptation...