Adam Clarke on Romans 11:10

Let their eyes be darkened - All these words are declarative, and not imprecatory. God declares what will be the case of such obstinate unbelievers; their table, their common providential blessings, will become a snare, a trap, a stumbling block, and the means of their punishment. Their eyes will be more and more darkened as they persist in their unbelief, and their back shall be bowed down always; far from becoming a great and powerful nation, they shall continue ever in a state of abject slavery and oppression, till they acknowledge Jesus as the promised Messiah, and submit to receive redemption in his blood.