Psalm 34:21 essentially expresses the idea that wickedness and evil actions ultimately lead to the downfall of those who engage in them, while those who oppose the righteous will face judgment and condemnation. Let's break it down:

"Evil shall kill the wicked": This part suggests that the very nature of evil acts will bring about the destruction of the wicked. The consequences of their actions, whether through internal corruption, societal backlash, or divine retribution, will lead to their demise. It's a statement about the inherent destructiveness of wickedness.

"Those who hate the righteous shall be condemned": This signifies that those who harbor hatred and animosity toward the righteous—those who strive to live according to God's will and moral principles—will be judged and found guilty. Their hatred is seen as a rejection of goodness and justice, leading to their condemnation.

In essence, the verse highlights:

The self-destructive nature of evil: Evil deeds have inherent consequences that ultimately harm the evildoer.
The condemnation of those who oppose righteousness: Hatred and opposition to goodness will not go unpunished.

The verse conveys a sense of moral order in the world, where wickedness is ultimately defeated and righteousness is vindicated.