Allah is perfect in His strength and in His firmness.
The attribute of al-Qawi pertains to the perfection of His power, while the attribute of al-Matin is the vehemence, the all-pervasive action of this strength. None can be saved from this strength; no force can oppose it. Nothing causes difficulty for it, nothing can weaken it, nor does that strength need any aid.
Allah has compassion and He has punishment. When He extends His compassion to His beloved servants, none can prevent this beneficence from reaching its destination, nor can any conceivable power prevent His vengeance, anger, and punishment from hitting its target. The servant should hope for all good and beauty to come from Allah, and should fear only Allah's punishment. Thus all other fears disappear from the hearts of servants who are attached to their Lord.
'Abd al-Matin is the servant to whom the mystery of the attribute of the all-pervasive strength of Allah is given. That strength makes him hold to his religion with such strength and patience that nothing can tempt him away from it, no difficulty will tire him, and nothing can separate him from the Truth. In the defense of the Truth, no one can frighten him nor silence him. His effect is upon everything, and none other that Allah can affect him.1
AL-QAWI AL-MATIN - The Perfectly Strong and Firm One
Strength is indicative of perfect power, and firmness is indicative of the intensity of the strength. Inasmuch as God Most High has the utmost of power and is perfect therein, He is strong; and inasmuch as He has intense power, He is firm (to the ultimate degree).2