This severe purgation comes to pass in few souls—in those alone whom He desires to raise to some degree of union by means of contemplation; and those who are to be raised to the highest degree of all are the most severely purged.  This happens as follows.  When God desires to bring the soul forth from its ordinary state—that is, from its natural way and operation—to a spiritual life, and to lead it from meditation to contemplation, which is a state rather heavenly than earthly, wherein He communicates Himself through union of love, He begins at once to communicate Himself to the spirit, which is still impure and imperfect, and has evil habits, so that each soul suffers according to the degree of its imperfections; and at times this purgation is in some ways as grievous to the soul whom it is preparing for the reception of perfect union here below as is that of purgatory, wherein we are purged in order to see God in the life to come.  St John of the Cross ‘Living Flame of Love’

Lamentations Chapter 3

I am the man who has seen affliction under the rod of His wrath;
He has driven and brought me into darkness without any light;
surely against me He turns His hand again and again the whole day long.
He has made my flesh and my skin waste away, and broken my bones;
He has besieged and enveloped me with bitterness and tribulation;
He has made me dwell in darkness like the dead of long ago.
He has walled me about so that I cannot escape; He has put heavy chains on me;
though I call and cry for help, He shuts out my prayer;
He has blocked my ways with hewn stones, He has made my paths crooked.
He is to me like a bear lying in wait, like a lion in hiding;
He led me off my way and tore me to pieces; He has made me desolate;
He bent His bow and set me as a mark for His arrow.
He drove into my heart the arrows of His quiver;
I have become the laughingstock of all peoples, the burden of their songs all day long.
He has filled me with bitterness, He has sated me with wormwood.
He has made my teeth grind on gravel, and made me cower in ashes;
my soul is bereft of peace, I have forgotten what happiness is;
so I say, “Gone is my glory, and my expectation from the LORD.”
Remember my affliction and my bitterness, the wormwood and the gall!
My soul continually thinks of it and is bowed down within me.
But this I call to mind, and therefore I have hope:
The steadfast love of the LORD never ceases, His mercies never come to an end;
they are new every morning; great is thy faithfulness.
“The LORD is my portion,” says my soul, “therefore I will hope in him.”