Perseverance – yes, more and more one sees that it is the great thing. But there is a thing which must not be overlooked. Perseverance is not hanging on to some course which we have set our minds to, and refusing to let go. It is not even a matter of getting a bulldog grip on the faith and not letting the devil pry us loose from it – though many of the saints made it look that way. Really, there is something lacking in such a hope as that. Hope is a greater scandal than we think. I am coming to think that God (may He be praised in His great mystery) loves and helps best those who are so beat and have so much nothing when they come to die that it is almost as if they had persevered in nothing but had gradually lost everything, piece by piece, until there was nothing left but God. Hence, perseverance is not hanging on, but letting go. That of course is terrible. But as you say so rightly, it is a question of His hanging on to us, by the hair of the head, that is from on top and beyond, where we cannot see or reach. What man can see the top of his own head? If we reach it – this we can do – we stand a good chance of interfering with God’s grip (may He forgive us).
Thomas Merton, in a letter to Dorothy Day dated February 4th 1960. From The Hidden Ground of Love: Letters by Thomas Merton.