[God] is always helping and providing us with salvation. The term “protector,” you see, is a metaphor from those thrusting their own shields among the enemy and by protection from these often sheltering others and freeing them from every disaster.
"My soul shall be patient for the Lord:" that hereafter it may be filled with dainties incorruptible, meanwhile, while here it remains, my soul shall be patient for the Lord. "For He is our Helper and Defender" [Psalm 33:20]: our Helper He is, while we endeavour after Him; and our Defender, while we resist the adversary.
When the psalmist says “he waits,” he indicates the endurance of the Christian … since it is endurance that makes the martyrs glorious, that watches over the good things of our faith, that conquers everything that stands against us, not by fighting against God’s will, but by enduring, not by complaining, but by giving thanks. Endurance suppresses deceptive luxury, it overcomes the heat of anger, it removes the jealousy that lays waste the human race, it renders people gentle, it smiles appropriately at the kind, and it sets the cleansed in good order for the rewards that are to come. Endurance wipes away the dregs of every pleasure; it makes souls appear bright. Through endurance we serve as God’s soldiers, through it we conquer the devil, through it we arrive as the blessed to his heavenly kingdom, for it is written, “in your endurance you will gain possession of your souls.”
The psalmist’s word waits reflects the patience of the Christian.… Patience is what makes glorious martyrs, what guards the blessings of our faith, what conquers all adversity not by wrestling but by enduring, not by grumbling but by giving thanks. Patience represses the extravagance that beguiles us. It overcomes hot anger, it removes the envy that ravages the human race, it makes people gentle, it smiles becomingly on the kind, and it orders people who are cleansed to attain the rewards that are to come. Patience wipes away the dregs of all pleasure; patience makes souls pure. Through patience we soldier for Christ, through it we conquer the devil, through it we blessedly attain the kingdom of heaven. As Scripture says, “In your patience you shall possess your souls.”
[AD 428] Theodore of Mopsuestia on Psalms 33:20