AMBROSIASTER:
By treasure, Paul meant the sacrament of God in Christ, which is made manifest to believers but which has been concealed from unbelievers with a veil. Just as a treasure is put in a hidden place, the sacrament of God is hidden within a person, in his heart. The reference to earthen vessels is an allusion to the weakness of human nature, which can do nothing unless empowered by God.
ORIGEN:
For God delivers us from afflictions not when we are no longer in affliction (… Paul says “we are afflicted in every way,” as though there were never a time when we were not afflicted), but when in our affliction we are not crushed because of God’s help. “To be afflicted,” according to a colloquial usage of the Hebrews, has the meaning of a critical circumstance that happens to us without our free choice, while “to be crushed” implies our free choice and that it has been conquered by affliction and given into its power. And so Paul is right when he says, “We are afflicted in every way but not crushed.”