Thou hast fed us with bread of tears, etc. By these forms of expression, they depict the greatness of their grief, and the long continuance of their calamities; as if they had said, We are so filled with sorrow, that we can contain no more. [1] They add, in the following verse that they were made a strife to their neighbors This admits of being explained in two ways. It means either that their neighbors had taken up a quarrel against them; or that, having obtained the victory over them, they were contending about the spoil, as is usually the case in such circumstances, each being eager to drag it to himself. The former interpretation, however seems to be the more suitable. The people complain that, whereas neighborhood ought to be a bond of mutual goodwill, they had as many enemies as neighbors. To the same purpose is their language in the second clause, They laugh at us among themselves; that is to say, They talk among themselves by way of sport and mockery at our adversities. To encourage and stir themselves up to repentance, they ascribe all this to the judgment of God, in whose power it is to bend the hearts of men. Since we are all at this day chargeable with the same sins, it is not surprising that our condition is in no degree better than was theirs. But the Holy Spirit having inspired the prophet to write this form of prayer for a people who felt their condition to be almost desperate, it serves to inspire us with hope and boldness, and to prevent us from giving up the exercise of prayer, under a consciousness of the greatness of our guilt. The seventh verse is a repetition of the third; and this repetition is undoubtedly intended as a means of surmounting every obstacle. God did not here intend to endite for his people a vain repetition of words: his object was to encourage them, when bowed down under the load of their calamities, boldly to rise up, heavy though the load might be. This ground of support was often presented to them; and it is repeated the third time in the concluding verse of the psalm.

Footnotes

1 - "There cannot," says Bishop Horne, "be a more striking picture of Zion in captivity! Her bread is dipped in tears; and her cup is filled to the brim with them: no time is free from grief and lamentation!"

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 Psalm 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.

Thou feedest them with the bread of tears - They have no peace, no comfort, nothing but continual sorrow.
In great measure - שליש shalish, threefold. Some think it was a certain measure used by the Chaldeans, the real capacity of which is not known. others think it signifies abundance or abundantly.

Thou feedest them with the bread of tears,.... With tears instead of bread, having none to eat; or their bread is mingled with their tears, "dipped" therein, as the Targum; such was their constant grief, and the occasion of it, that they could not cease from tears while they were eating their meals, and so ate them with them (n):
and givest them tears to drink in great measure; or the wine of tears "three fold", as the Targum. Jarchi interprets it of the captivity of Babylon, which was the third part of the two hundred and ten years of Israel's being in Egypt; which exposition, he says, he learned from R. Moses Hadarsan; but he observes, that some interpret it of the kingdom of Grecia, which was the third distress: and so Kimchi and Arama explain it of the third captivity; but Menachem, as Jarchi says, takes "shalish" to be the name of a drinking vessel, and so does Aben Ezra; the same it may be which the Latins call a "triental", the third part of a pint; unless the Hebrew measure, the "seah", which was the third part of an "ephah", is meant; it is translated a "measure" in Isaiah 40:12 and seems to design a large one, and so our version interprets it; compare with this Isaiah 30:20.
(n) "----lachrymisque suis jejunia pavit", Ovid. Metamorph. l. 4. Fab. 6.

bread of tears--still an Eastern figure for affliction.