AD-DARR – THE CREATOR OF THE HARMFUL
Most references wherein these Attributes are discussed have combined both Attributes together. Combining both of these Attributes is better: it neither conveys a stronger meaning of the Almighty's Power to do whatever He wills, however He wills; none benefits nor harms others besides Him.
He decrees harm to some of His servants and affects His decree through certain means. He is the Wise One in whatever He does, the most Merciful in His judgment. If He decrees some harm, it is only for the sake of the general good, and if He decrees an ailment, it is but the useful medicine in the life of this world and the life hereafter.
Allah has said, "And if Allah should touch you with adversity, there is no remover of it except Him. And if He touches you with good – then He is over all things competent." (Quran, 6:17).
"Say, "I possess not for myself any harm or benefit except what Allah should will. For every nation is a (specified) term. When their time has come, then they will not remain behind an hour, nor will they precede (it)." (Quran, 10:49)