Final perseverance is a divine gift so great, that, as the holy Council of Trent has declared, it is a wholly gratuitous gift, and one that cannot be merited by us. But, as St. Augustine teaches us, all those obtain perseverance from God who ask it of him; and as Father Suarez says, they infallibly obtain it if they are diligent to the end of life in praying God for it; because, as Cardinal Bellarmine writes: This perseverance is daily to be sought, that it may be daily obtained.[177] Now, if it is true, which I consider certain, according to the present very general opinion, as I shall presently demonstrate in chap. 5th—if it is true that all the graces which are bestowed on us by God pass through the hands of Mary, it must also be true that only through Mary can we hope for and obtain this great gift of perseverance. And we certainly shall obtain it, if, with confidence, we always ask it of Mary. She herself promises this grace to all those who serve her faithfully in this life. “They that work by me shall not sin; they that explain me shall have life everlasting:”[178] which words the holy Church puts into the mouth of Mary on the Feast of her Conception. In order that we may be preserved in the life of divine grace, spiritual strength is necessary to resist all the enemies of our salvation. Now, this strength can only be obtained by means of Mary: Mine is this strength, says Mary: “Mea est fortitudo.” God has intrusted this gift to my hand, that I may bestow it on my devoted servants. “By me kings reign:” “Per me reges regnant.”[179] By me my servants reign, and rule their senses and their passions, and thus make themselves worthy of reigning eternally in heaven. Oh, what strength have the servants of this great Lady to conquer all the temptations of hell! Mary is that tower spoken of in the holy Canticles: “Thy neck is as the tower of David, which is built with bulwarks; a thousand bucklers hang upon it, all the armor of valiant men.”[180] She is like a strong tower of defence for her lovers, who take refuge with her in the day of battle; in her all her devoted servants find shields and weapons of every kind to defend themselves against the powers of hell. For this reason, the most holy Virgin is called a plane-tree: “As a plane-tree by the water in the streets was I exalted.”[181] This passage is explained by Cardinal Hugo, who tells us that the plane-tree has leaves like shields.[182] And by this is explained the defence that Mary affords those who take refuge with her. The blessed Amadeus gives another explanation, and says that she is called a plane-tree because, as the plane-tree, with its shade, protects the traveller from the heat of the sun and from the rain, so, under the mantle of Mary, men find shelter from the heat of their passions and the fury of temptations.[183]