From à Kempis again, on resisting temptation:

Fire tempers iron and temptation steels the just. Often we do not know what we can stand, but temptation shows us what we are. Above all, we must be especially alert against the beginnings of temptation, for the enemy is more easily conquered if he is refused admittance to the mind and is met beyond the threshold when he knocks.

Someone has said very aptly: “Resist the beginnings; remedies come too late, when by long delay the evil has gained strength.” First, a mere thought comes to mind, then strong imagination, followed by pleasure, evil delight, and consent. Thus, because he is not resisted in the beginning, Satan gains full entry. And the longer a man delays in resisting, so much the weaker does he become each day, while the strength of the enemy grows against him.

Some suffer great temptations in the beginning of their conversion, others toward the end, while some are troubled almost constantly throughout their life. Others, again, are tempted but lightly according to the wisdom and justice of Divine Providence Who weighs the status and merit of each and prepares all for the salvation of His elect.

We should not despair, therefore, when we are tempted, but pray to God the more fervently that He may see fit to help us, for according to the word of Paul, He will make issue with temptation that we may be able to bear it. Let us humble our souls under the hand of God in every trial and temptation for He will save and exalt the humble in spirit.

In temptations and trials the progress of a man is measured; in them opportunity for merit and virtue is made more manifest.

When a man is not troubled it is not hard for him to be fervent and devout, but if he bears up patiently in time of adversity, there is hope for great progress.

Some, guarded against great temptations, are frequently overcome by small ones in order that, humbled by their weakness in small trials, they may not presume on their own strength in great ones. -- The Imitation of Christ, Bk. 1, Ch. 13.

There is some critical, need-to-know information in that last sentence.