The Sermon on the Mount

Blessed are the merciful: for they shall obtain mercy.

The undisputable fact is that the entire human race, including every single person everywhere, is in need of divine mercy. Without mercy divine justice would be swift and complete, and the sentence of death would be carried out. Now the unsaved are in a season of mercy in this gospel age while the saved have obtained eternal mercy through faith in the Lord Jesus.
We must remember that the Sermon on the Mount was meant in particular to believers as evidenced in many places including the last Beatitude which speaks of persecution for Christ’s sake. So this mercy of which Christ’s speaks does indeed apply most fully to us believers. And the principle is very obvious - those who have been shown mercy should show mercy in return. Of course this divine mercy we have received came forth from the divine love which is God Himself. True love is merciful.
So often believers feel a calling to judgment that is so strong and without any real mercy that it entirely misrepresents the heart of God and it repels sinners. These believers rehearse the law of Moses in a sincere attempt to make sinners aware of their sin and repentant about it. Of course many of that kind of believer believes that a sinner cannot repent unless God gifts him with such repentance, so the Moses road approach is so much window dressing.
We are called to preach the gospel without attaching the law of Moses. Most of the messages in the Book of Acts were without any litany of the Old Testament law, and in fact the core message was the death and resurrection of Jesus the Messiah. The writer of Hebrews tells us that the main fear in man is death and the uncertainty about what follows that death. And the gospel is what addresses that issue including the gospel in a verse John 3:16. Sinners need mercy not a laundry list of their sins, and only the Spirit can draw a sinner to Jesus Christ regardless of how wonderful and organized your evangelistic presentation might be.

Matt.9:12-13 - But when Jesus heard that, he said unto them, They that be whole need not a physician, but they that are sick.
But go ye and learn what that meaneth, I will have mercy, and not sacrifice: for I am not come to call the righteous, but sinners to repentance.

We believers still battle with our old nature, and that nature is filled with self righteousness and judgment. We tend to show mercy when we deem it warranted or when someone deserves it, but that is not what God commands us to do. We should be people after God’s own heart which Jesus said was mercy. You can perform all the religious oblations and serve faithfully in your local church construct, but if you are not a person filled with mercy that manifests itself through your very life than you are not an imitator of Jesus. And this kind of mercy is not easy to live since it includes showing mercy to many people who are the product of their own sinful choices - just like us if we are honest. But once a sinner arrives on the God side of grace the flesh sets out to turn around and judge the sinners from whence you just came. It is satisfying to the flesh even though such an attitude is an affront to the mercy and grace you just received.
Showing mercy goes against our propensity to meet out verbal justice and our willingness to verbally identify the sins of others while dealing with our own sins in the solitude of our own conscience. Mercy is foreign to the fallen nature and even when a believer shows very little to others, when he finds himself exposed in some grievous sin, that same merciless man begs for it personally. But this verse tells us that the way to receive mercy is to show it. How do we as believers show this mercy?
We must show mercy to unbelievers in order to reveal to them God's heart and His desire for their redemption. That does not mean we should condone their sin, but it also does not mean we need to publicly castigate them and prove to the ecclesiastical world our doctrinal purity. We live in an age where information travels quickly and through many avenues. And rarely do we get the entire story but not so rarely do we form concrete judgments about people. We should not desire information about people, and we should offer mercy to those with whom we have no relationship.
To masticate on the sins of the lost serves no redemptive purpose and that kind of self righteousness has often confused unsaved people into believing that our faith is one of moral alignment. Any kind of moral alignment is a result of God’s redemptive mercy and certainly not a prerequisite. It is residual and not foundational. In fact, if we are painfully honest, we still have much moral territory in our lives that is in need of alignment. Even when the bigger foxes in our lives have been slain, there are still many little ones that roam with all too much freedom. Again, we as believers are still in need of God’s mercy. God states that here:

Heb.4:16 - Let us therefore come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need.

We must also show each other mercy. This again is most difficult since we tend to show mercy to those we like and judgment to those of whom we are not fond. But showing mercy is not a divine suggestion, it is a command. And it is an integral part of exhibiting the kingdom of God and the Person of Christ worked out among believers. It is a very sad day when the distinguishing feature of the Christian community in this western culture is what we are against, and that much evangelical labor is given to return to and preserve some founding father’s mirage that never existed in the first place. All of which takes place in cubicle without mercy.
In general, the one aspect of doctrine that must be confronted when it is compromised is salvation by grace through faith in Jesus Christ alone. The issue of redemption is the one aspect of Christian doctrine that must be corrected and even rebuked. That is a non-negotiable. But even that must be approached with a sense of humility and extending the hope for repentance. But as it pertains to showing mercy among the community of believers, we should be aggressively merciful.

I Tim.1:16 - Howbeit for this cause I obtained mercy, that in me first Jesus Christ might shew forth all longsuffering, for a pattern to them which should hereafter believe on him to life everlasting.

Like Paul, let us show a pattern of mercy that those around us might see the heart of God revealed in His Son the Lord Jesus.