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 28:1An earnest cry for divine aid against his enemies, as being also those of God, is followed by the Psalmist's praise in assurance of a favorable answer, and a prayer for all God's people. (Psa 28:1-9)
my rock-- (Psa 18:2, Psa 18:31).
be not silent to me--literally, "from me," deaf or inattentive.
become like them, &c.--share their fate.
go down into the pit--or, "grave" (Psa 30:3).
psa 28:2lift up my hands--a gesture of prayer (Psa 63:4; Psa 141:2).
oracle--place of speaking (Exo 25:22; Num 7:89), where God answered His people (compare Psa 5:7).
psa 28:3Draw me not away--implies punishment as well as death (compare Psa 26:9). Hypocrisy is the special wickedness mentioned.
psa 28:4The imprecation is justified in Psa 28:5. The force of the passage is greatly enhanced by the accumulation of terms describing their sin.
endeavours--points out their deliberate sinfulness.
psa 28:5Disregard of God's judgments brings a righteous punishment.
destroy . . . build . . . up--The positive strengthened by the negative form.
psa 28:6supplications--or, "cries for mercy."
psa 28:7The repetition of "heart" denotes his sincerity.
psa 28:8The distinction made between the people.
their strength--and the anointed--may indicate Absalom's rebellion as the occasion.
psa 28:9The special prayer for the people sustains this view.
feed them--as a shepherd (Psa 23:1, &c.).