The answer - Jalal al-Din Rumi

"Allah, Allah!" cried the sick man, racked with pain the long night through; 

Till with prayer his heart grew tender, till his lips like honey grew.

But at morning came the tempter, said, "Call louder, child of pain! 

See if Allah ever hears, or answers, 'Here am I!' again."

Like a stab the cruel cavil through his brain and pulses went; 

To his heart an icy coldness, to his brain a darkness sent.

Then before him stands Elias, says, "My child, why thus dismayed? 

Dost repent thy former fervour? Is thy soul of prayer afraid?"

"Ah I" he cried, "I've called so often; never heard the 'Here am I:' 

And I thought God will not pity, will not turn on me his eye."

Then the grave Elias answered, "God said, 'Rise, Elias; go 

Speak to him the sorely tempted; lift him from his gulf of woe.

'Tell him that his very longing is itself an answering cry;

That his prayer, "Come, gracious Allah!" is my answer, "Here am I." ' "

Every inmost aspiration is God's angel undefiled; 

And in every "O my Father" slumbers deep a " Here, my child!"

---

Jalal al-Din Rumi (1207 - 1273) Persia (Iran)

Translated by J.F. Clarke

Source: Songs of the soul: gathered out of many lands and ages, by Samuel Irenaeus Prime, Robert Carter and Brothers, 1874

NB: In the book the author is written thus "Dscheladeddin" but I am pretty sure this is actually Rumi, and the name is a mis-heard version of Jalal al-Din!