Well, I finally found the source of this quote of which I first heard from Dr. Stephen Tong's mouth.
TABLE TALKS: OF JUSTIFICATION, by Dr. Martin Luther:
CCCXIX, 319
I never Work better than when I am inspired by anger; when I am angry, I
can write, pray, and preach well, for then my whole temperament is
quickened, my Understanding sharpened, and all mundane vexations and
temptations depart.
God uses our anger, but this does not mean that we can use this statement anytime we like, especially when we're angry.
Psalms 76:10 Surely the wrath of man shall praise You; With the remainder of wrath You shall gird Yourself.
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