This is an explanation by the Spiritual Director FR Snow to his ward or child Theresa Helena Higginson. It can be found in the Book of her life written by Lady Cecil Kerr and published by Sands and Company
Father Snow replied as follows:
My DEAR CHILD.
"You must distinguish in your mind between a perfect state of life and a state of perfection. The religious is the most perfect state of life but anyone can with God's grace reach a state of perfection in any state of life. And we have also to distinguish between what is best and more perfect in itself and what is best and more perfect with regard to each individual. Now no one can possibly be in a more perfect state than to fulfill in everything the Will of God and have one's will made one with the Will of God, and he gives most glory to God who most perfectly fulfills His Will. So if one person in obedience to God's Will takes no vows and if another in obedience to God's Will takes private vows and another in obedience to God's Will takes vows in religion, all three cannot do anything more perfect or give more glory to God in that particular matter. The father of St. Lewis Bertrand after the death of his first wife had an ardent desire to become a Carthusian in order to devote the remainder of his life to prayer and penance. On his way to the Carthusian monastery to ask for the habit. St. Bruno and St. Vincent Ferrar appeared to him and assured him that it was not God's Will that he should become a monk but that he was to marry a second time and serve God in the world; whereupon he married again and became the father of a great saint. And he could not have done anything more perfect or given more glory to God. And though it is true to say that the state of life of a Carthusian is a more perfect state than that of a married man in the world, yet there is no reason why a man like the father of St. Lewis might not reach a much higher state of perfection and union with God than many a Carthusian.
"The application of all this to yourself is simple enough, and I hardly need make it. The grace of God urged you to take private vows, even before you properly knew the meaning of them, and the same grace urged you to renew them at, your first Communion and many times afterwards, and as far as I know you have never had any indication whatever that it is God's Will that you should take vows in religion.
"You may therefore conclude that you are perfectly doing His Will in not taking vows in religion-and giving Him more glory thereby. He has been pleased to make use of you for His glory first in one place and then in another and it may be His Will to do so again in the future. Therefore, you would be doing wrong to tie yourself to any particular place unless you had strong indications that it was God's Will you should do so.
"I hope this makes clear what you wanted to know. If not I will write again if you will let me know exactly what you want.
"With love to my sisters and kind remembrances to all "
Yours affectionately in Christ
" ALFRED SNOW."