It is crucial to understand the meaning and manifestation of mercy so you can use it rather than abuse it.
Mercy is the flip-side of grace. Grace is blessing someone with what they don’t deserve and mercy is withholding what they do deserve. You can’t extend grace without having mercy.
The Greek word used in here, “eleemon” means essentially the same as its English counterpart, "merciful." However, in all likelihood Jesus spoke in Aramaic, and the idea behind His statement about mercy come from Old Testament—that is, Hebrew—usage and teaching. The word He would have used is the Hebrew and Aramaic “chesed.”
William Barclay's Daily Study Bible commentary on Matthew states regarding this word:
“It does not mean only to sympathize with a person in the popular sense of the term; it does not mean simply to feel sorry for some in trouble.” Chesed,” mercy, means the ability to get right inside the other person's skin until we can see things with his eyes, think things with his mind, and feel things with his feelings.”
"Clearly this is much more than an emotional wave of pity; clearly this demands a quite deliberate effort of the mind and of the will. It denotes a sympathy which is not given, as it were, from outside, but which comes from a deliberate identification with the other person, until we see things as he sees them, and feel things as he feels them. This is sympathy in the literal sense of the word. Sympathy is derived from two Greek words, syn which means together with, and paschein which means to experience or to suffer. Sympathy means experiencing things together with the other person, literally going through what he is going through." (p. 103)
So the translation of the fifth beatitude might read:
“O the blessedness of the man who gets right inside other people, until he can see with their eyes, think with their thoughts, feel with their feelings, for he who does that will find others do the same for him, and will know that that is what God in Jesus Christ has done!”
You need to understand mercy so you can become merciful as God demands.
As you become merciful to others, you receive mercy from God.
Let me share one more very contemporary reason for understanding mercy. Mercy can be used against you!
For example, those who believe in open borders and amnesty for those illegally crossing our Southern border make the claim that prosecuting these illegals or deporting them is unmerciful. They cite the thousands of children flooding into our country to appeal to our sense of mercy while ignoring the obvious violations of law and the tens of thousands of adults who are also crowding into border states. If anyone tries to point out the manifold problems and potential dangers created by unchecked immigration, they are shamed for being unmerciful.
Mercy operates within the context of justice. Jesus made that clear in Matthew 23:23 - "Woe to you, teachers of the law and Pharisees, you hypocrites! You give a tenth of your spices--mint, dill and cumin. But you have neglected the more important matters of the law--justice, mercy and faithfulness. You should have practiced the latter, without neglecting the former."
Let's have mercy on innocent children who have been lured to our land by lies but let's also do justice to our laws and be faithful to our Constitution!