Romans 11:9

And David saith, Let their table be made a snare, and a trap, And a stumblingblock and a recompense unto them: Let their eyes be darkened that they may not see, And bow thou down their back always.

Paul brought this forward from Psalms 69:19 for the purpose of further proving from the scriptures that the hardening of Israel had long been foretold by the word of God.

Let their eyes be darkened ... is a clear reference to hardening.

Snare ... trap ... stumblingblock ... As Murray said, these words are closely related, and precise distinctions of meaning are not to be pressed.[10] That "their table" is to be made such, is a reference to the fact that the very devices which God had provided, by which Israel should have been restrained and purified, such as the law of Moses and all of the religious institution, (those very things) became the occasion of their fall, not through God's fault at all, but through their abuse of sacred privilege. This also may have reference to such things as the monarchy, which, though contrary to God's will, was permitted them as something they ardently wanted, being in that sense "their table," but being at the same time the very thing that blinded them to the Lord when he came. See under Romans 11:1.

Their table ... is also suggestive of what Jesus said regarding the temple, "Behold your house is left unto you desolate" (Matthew 23:38), indicating that even divine things, set up by God himself, if perverted and debased to serve human ends, lose all their sanctity, thus being no longer God's but "theirs."

Bow down thou their back always ... refers to the perpetual nature of the sentence imposed upon Israel, not referring exclusively to their being perpetually subjected, but to the endurance of the hardened condition finally imposed. Certainly, in this place, there is no suggestion that after certain centuries have passed, or after the Gentiles are saved, God will commute the sentence and restore them!