A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
psa 35:1The Psalmist invokes God's aid, contrasting the hypocrisy, cunning, and malice of his enemies with his integrity and generosity. The imprecations of the first part including a brief notice of their conduct, the fuller exposition of their hypocrisy and malice in the second, and the earnest prayer for deliverance from their scornful triumph in the last, are each closed (Psa 35:9-10, Psa 35:18, Psa 35:27-28) with promises of praise for the desired relief, in which his friends will unite. The historical occasion is probably 1Sa. 24:1-22. (Psa. 35:1-28)
God is invoked in the character of a warrior (Exo 15:3; Deu 32:41).
psa 35:3fight against--literally, "devour my devourers."
stop the way against--literally, "shut up" (the way), to meet or oppose, &c.
I . . . thy salvation--who saves thee.
psa 35:4(Compare Psa 9:17).
devise my hurt--purpose for evil to me.
psa 35:5(Compare Psa 1:4) --a terrible fate; driven by wind on a slippery path in darkness, and hotly pursued by supernatural violence (Sa2 24:16; Act 12:23).
psa 35:7net in a pit--or, "pit of their net"--or, "net-pit," as "holy hill" for "hill of holiness" (Psa 2:6); a figure from hunting (Psa 7:15). Their imprecations on impenitent rebels against God need no vindication; His justice and wrath are for such; His mercy for penitents. Compare Psa 7:16; Psa 11:5, on the peculiar fate of the wicked here noticed.
psa 35:10All my bones--every part.
him that spoileth him--(Compare Psa 10:2).
psa 35:11False witnesses--literally, "Witnesses of injustice and cruelty" (compare Psa 11:5; Psa 25:19).
psa 35:12Though they rendered evil for good, he showed a tender sympathy in their affliction.
spoiling--literally, "bereavement." The usual modes of showing grief are made, as figures, to express his sorrow.
psa 35:13prayer . . . bosom--may denote either the posture--the head bowed--(compare Kg1 18:42) --or, that the prayer was in secret. Some think there is a reference to the result--the prayer would benefit him if not them.
psa 35:14behaved--literally, "went on"--denoting his habit.
heavily--or, "squalidly," his sorrowing occasioning neglect of his person. Altogether, his grief was that of one for a dearly loved relative.
psa 35:15On the contrary, they rejoiced in his affliction. Halting, or, "lameness," as in Psa 38:17 for any distress.
abjects--either as cripples (compare Sa2 4:4), contemptible; or, degraded persons, such as had been beaten (compare Job 30:1-8).
I knew it not--either the persons, or, reasons of such conduct.
tear me, and ceased not--literally, "were not silent"--showing that the tearing meant slandering.
psa 35:16mockers--who were hired to make sport at feasts (Pro 28:21).
psa 35:17darling--(Compare Psa 22:20-21).
psa 35:18(Compare Psa 22:22).
psa 35:19enemies wrongfully--by false and slanderous imputations.
wink with the eye--an insulting gesture (Pro 6:13).
without a cause--manifests more malice than having a wrong cause.
psa 35:20deceitful matters--or, "words of deceit."
quiet in the land--the pious lovers of peace.
psa 35:21On the gesture compare Psa 22:7; and on the expressions of malicious triumph, compare Psa 10:13; Psa 28:3.
psa 35:23(Compare Psa 7:6; Psa 26:1; Th2 1:6). God's righteous government is the hope of the pious and terror of the wicked.
psa 35:25swallowed him up--utterly destroyed him (Psa 21:9; Lam 2:16).
psa 35:26clothed--covered wholly (Job 8:22).
psa 35:27favour . . . cause--delight in it, as vindicated by Thee.
Let the Lord, &c.--Let Him be greatly praised for His care of the just.
psa 35:28In this praise of God's equitable government (Psa 5:8) the writer promises ever to engage.