FAUSTUS: No, Faustus, curse thyself, curse Lucifer,
That hath deprived thee of the joys of heaven.
(The clock striketh twelve.)
O, it strikes, it strikes! Now, body, turn to air,
Or Lucifer will bear thee quick to hell.
(Thunder and lightning.)
O soul, be changed into little water drops,
And fall into the ocean, ne’er be found!
My God, my God, look not so fierce on me!
(Enter Devils.)
Adders, and serpents, let me breathe a while!
Ugly hell, gape not. Come not Lucifer!
I’ll burn my books! Ah, Mephistophilis!
(Exeunt Devils with Faustus.)

Christopher "Kit" Marlowe (1564-1593) English dramatist and poet

The Tragicall History of the Life and Death of Doctor Faustus, Act 5, sc. 2 (sc. 19), l. 1498ff (1594; 1604 “A” text)
    (Source)

The B-Text (1594; 1616), l. 2081ff, is largely the same, with minor punctuation changes, except that rather than cry "My God, my God," Faustus cries "O mercy, heaven!"