Passage
Oh that thou wouldest slay the wicked, O God! And ye men of blood, depart from me.
Oh that thou wouldest slay the wicked, O God! And ye men of blood, depart from me.
Psalms 139:17 But how precious are thy thoughts unto me, O God! how great is the sum of them!
Psalms 139:18 [If] I would count them, they are more in number than the sand. When I awake, I am still with thee.
Psalms 139:19 Oh that thou wouldest slay the wicked, O God! And ye men of blood, depart from me.
Psalms 139:20 For they speak of thee wickedly, they take [thy name] in vain, thine enemies.
Psalms 139:21 Do not I hate them, O Jehovah, that hate thee? and do not I loathe them that rise up against thee?
The verse centers on "thou", "wouldest", "slay", "wicked", "blood", and "depart". It is saying that the verse draws attention to "thou" and "wouldest", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 18's "If I would count them they are..." into verse 20's "For they speak of thee wickedly they...", so "thou" and "wouldest" belong inside that flow. In Psalms context, the local focus is worship, trust, the LORD's kingship, and covenant mercy.
A plain takeaway is to answer the verse's own emphasis on "thou" and "wouldest" with trust shaped by these words, not by a vague optimism outside the passage.