But we have this treasure in earthen vessels, that the excellency of the power may be of God, and not of us.
'Lest any should say, How is it that we enjoy such unspeakable glory in a mortal body? he replies, This is one of the most marvelous proofs of God's power, that an earthen vessel could bear such splendour and keep such a treasure ("the light of the knowledge of the glory of God")' (Chrysostom). The fragile "earthen vessel" is the body, the "outward man" (2 Corinthians 4:16: cf. 2 Corinthians 4:10) liable to afflictions and death. So the light in Gideon's pitchers (Judges 7:16-20; Judges 7:22). The ancients often kept their treasures in vessels of earthenware. 'There are earthen vessels which yet are clean, and golden vessels which are filthy' (Bengel).
That the excellency of the power ... - that the power of the ministry (the Holy Spirit), in its surpassing "excellency," exhibited in winning souls (1 Corinthians 2:4) and in sustaining us ministers, might be ascribed solely to God. God often allows the vessel to be chipped and broken, that the excellency of the treasure within and of the power may be all His (2 Corinthians 4:10-11; John 3:30).
May be of God, and not of us - rather, as Greek, 'may be God's (may be seen and thankfully (2 Corinthians 4:15) acknowledged to belong to God), and not (to come) from х ex (G1537)] us.' The power not merely comes from, but belongs to God continually, and is to be ascribed to him.