There are again others who go into religion on account of some natural defect, for instance, because they are lame, or blind of one eye, or ugly, or have some other similar defect. Thus many enter religion through disgust or weariness, or on account of disappointments and troubles which detach them from the love of creatures; they preserve them from the delusion of false appearances, and force them to enter into themselves; they purify their hearts; they cause goodness to take root in their souls; they give them a distaste for life in the world.
Some souls are preserved from the delusions of the world, and opened to the call of God, through sorrow, disgust or social rejection.
Would such souls have sought consolation only in God, if the world had loved them? Would they have known the sweetness of God, if the world had not maltreated and banished them from its society? It is God who permits such harsh treatment and refusals to befall them. He causes thorns to spring over all their pleasures, in order to prevent their reposing thereon. They would never have belonged to God, had the world desired them; and they would have been adverse to Him, had the world not been adverse to them. It is thus that the Lord breaks the fetters, by which the world held them in bondage.
“There are souls,” says St Francis de Sales, “who were the world to smile upon them, would never become religious; yet by means of contradictions and disappointments, they are brought to despise the vanities, and all allurements of the world, and understand its fallacy.”
“Our Lord has often made use of such means to call many persons to His service, whom He could not have otherwise. For although God is all-powerful and can do what He wills, yet He does not will to take away the liberty which He has given us; and when He calls us to His service, He will have us enter it willingly, and not by force or constraint.
Now, though these persons come to God, as it were, in anger against the world, which has displeased them, or on account of some troubles or afflictions which have tormented them, yet they do not fail to give themselves to God of their own free will; and very often such persons succeed very well in the service of God, and become great Saints, sometimes greater than those who have entered it with more evident vocations, or with far purer motives. God, very often in these cases, shows the greatness of His Wisdom and Divine Goodness. He draws good from evil by employing the intentions of these persons, which are by no means good in themselves, to make those persons, great servants of His Divine Majesty. Those whom the Gospel mentions as having been forced to partake of the feast, did not, on that account, relish it less.
“The Divine Artisan takes pleasure in making beautiful buildings with wood that is very crooked and has no appearance of being fit for anything; and, as a person who does not understand carpenter’s work, seeing some crooked wood in his shop, would be astonished to hear him say it was meant for making some fine work of art (for he would say, how often must the plane pass over it before it can be fit for such a work?)
So Divine Providence, usually makes masterpieces out of these crooked and sinister intentions. He makes the lame and blind come to His feast, to show us that we need not have two eyes or two feet to enter Paradise; that it is better to go to Heaven with one leg, one eye, or one arm, than to have two and be lost. Now this sort of people having entered religion in this way, have often been known to make great progress in virtue and persevere faithfully in their vocation.
http://papastronsay.com/fssr/Vocation/marks_of_vocation.html