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 101:2In this Psalm the profession of the principles of his domestic and political government testifies, as well as actions in accordance with it, David's appreciation of God's mercy to him, and His judgment on his enemies: and thus he sings or celebrates God's dealings. (Psa 101:1-8)
He avows his sincere purpose, by God's aid, to act uprightly (Gen 17:1; Psa 18:30).
psa 101:3set . . . eyes--as an example to be approved and followed.
no wicked thing--literally, "word," plan or purpose of Belial (Psa 41:8).
work of . . . aside--apostates.
not cleave to me--I will not be implicated in it (compare Psa 1:1-3).
psa 101:4A froward heart--or, "perverse heart" (Psa 18:26). Such a temper I will not indulge, nor even know evil or wickedness.
psa 101:5The slanderers and haughty persons, so mischievous in society, I will disown; but--
psa 101:6Mine eyes . . . upon--or, I will select reliable and honest men for my servants.
psa 101:7not dwell--literally, "not sit," or tarry, or be established.
psa 101:8will early--or, "diligently."
city of the Lord--or, "holy place" (Psa 48:2), where wicked men shall not be tolerated.