Thou feedest them with the bread of tears - literally, “Thou causest them to eat the bread of tears,” or of weeping. That is, their food was accompanied with tears; even when they ate, they wept. Their tears seemed to moisten their bread, they flowed so copiously. See the notes at Psalms 42:3.
And givest them tears to drink - So abundant were their tears that they might constitute their very drink.
In great measure - Or rather by measure; that is, abundantly. The word here rendered “great measure” - שׁלישׁ shâlı̂ysh - means properly a third, and is usually applied to a measure for grain - a third part of another measure - as, the third part of an ephah. See the notes at Isaiah 40:12. Then the word is used for any measure, perhaps because this was the most common measure in use. The idea seems to be, not so much that God gave tears to them in great measure, but that he measured them out to them, as one measures drink to others; that is, the cup, or cask, or bottle in which their drink was served to them was as if filled with tears only.