Psalm 139:19

Oh that you would slay the wicked, O God!
O men of blood, depart from me!
(ESV)

Have you ever prayed that way? You are just sick of the wrong that is going on around you, and you just cry out to God, asking Him to end it.

Even though it doesn't say so in this particular passage, we know why God tarries, why God stays His hand. It is His grace.

Consider the story of Jonah. Jonah wanted the evil people of the city of Nineveh to perish. He wanted them to pay for their crimes against humanity, and he did not want them to get right with God. So when God calls Jonah to go to that city, Jonah runs.

We know what happens next. God doesn't let Jonah get too far, and miraculously brings him, not only to a place of repentance, but also back to Nineveh.

After Jonah preaches, the people repent. Jonah isn't too happy about this so he goes and sits down outside of the city. He builds a little shelter and God causes a vine to grow up over Jonah to shade his head. The vine dies the next day, and Jonah gets mad about this as well. God asks Jonah if he is angry about the vine and Jonah responds that he is angry enough to die.

God's response in Jonah 4:10-11 is this:

"You pity the plant, for which you did not labor, nor did you make it grow, which came into being in a night and perished in a night. 11 And should not I pity Nineveh, that great city, in which there are more than 120,000 persons who do not know their right hand from their left, and also much cattle?"

He even mentioned the cows.

It isn't wrong to want the wickedness to stop, but keep in mind God's compassion, even for the cows.