Harmful blue-green algae blooms can devastate a fresh water ecosystem like a pond or lake. The bacteria that forms the scummy mats that cover the surface of a body of water are always present within the water. However, when conditions are just right, these bacteria can blossom rapidly—in a matter of days—into a harmful bloom that covers the entire body of water. Once the bloom begins to form, the disruptive effects on the ecosystem are immediate. Other living organisms in the watery environment begin to suffer from deadly toxins, lack of sunlight, insufficient oxygen, and other effects that trickle down the food web. This can lead to a large dying off event. But the harmful bloom doesn’t just affect organisms that live in the water. It can also harm organisms that drink the water, come into contact with it, or inhale the water droplets. Ultimately, the bloom itself will die off because there no longer remains enough nutrients to sustain it. In a sense, the bloom destroys itself. So, in short, the potential for a harmful blue-green algae bloom remains hidden in the water until, suddenly, it seems to explode from out of nowhere. It then begins to systematically destroy other living organism within the ecosystem until it ultimately succumbs to its own gluttonous appetite that leaves no nutrients to sustain its own life.

What’s the illustration here? Obviously, this is the nature of sin. Sin remains hidden under the surface, and, when the conditions are right, it erupts to harm others and self. One specific sin that is particularly sneaky in this way is the sin of bitterness. Bitterness can lay under the surface for a long, long time. Then, when conditions are just right, it breaks out. The outcome of a bloom of bitterness is always devastating. A small droplet of bitterness will rapidly grow until it strips away the very inheritance of eternal life that Christ offers us. How do we overcome this insidious sin?

Consider Matthew 5:44–45,

But I say to you, Love your enemies and pray for those who persecute you, so that you may be sons of your Father who is in heaven. For he makes his sun rise on the evil and on the good, and sends rain on the just and on the unjust (Matthew 5:44–45).

Focus on verse 44 through the first half of verse 45: But I say to you, Love your enemies and pray for those who persecute you, so that you may be sons of your Father who is in heaven. Follow Jesus’ logic here. Loving one’s enemies and praying for those who persecute you results in becoming a son of God the Father. This truth contains two implications:

Implication 1: You are not a son of God the Father due to your sinfulness in general.

Implication 2: You will not be a son of God the Father if you harbor bitterness for your enemies.

These implications are the reasons Jesus gives the command. He gives the command to wake us up to the reality that we are separated from God the Father by our sin. He gives the command to warn us that if we remain in our sin we will remain separated from God the Father. Another reason Jesus gives the command, though, is this: Our tendency due to our sinful flesh is to not love our enemies but to become embittered toward them. That is, our fallen, sinful natures prevent us from loving our enemies and propel us to harbor bitterness toward them. And that bitterness, like a harmful algae bloom, bides its time until conditions cause it to erupt in harmful desires for and acts of vengeance. Paul warns about this in Romans 12:19,

Beloved, never avenge yourselves, but leave it to the wrath of God, for it is written, “Vengeance is mine, I will repay, says the Lord” (Romans 12:19).

The command here is simple. We must not become embittered and seek vengeance. Rather, we should trust God to act justly. Our conundrum, though (as we’ve just pointed out) is that in our fallen nature we are bent to not love our enemies but rather harbor bitterness toward them. Likewise, we do not pray for those who persecute us but pine for vengeance. What’s the solution? How do we become sons of God the Father if we cannot overcome our inherent bent toward bitterness and vengeance? We need one who is already a son of the Father to show us the way. We need the Son.

Jesus, the Son of God, offers us the supreme example of loving one’s enemies rather than becoming embittered toward them. Consider 1 Peter 2:21–23,

For to this you have been called, because Christ also suffered for you, leaving you an example, so that you might follow in his steps. He committed no sin, neither was deceit found in his mouth. When he was reviled, he did not revile in return; when he suffered, he did not threaten, but continued entrusting himself to him who judges justly (1 Peter 2:21–23).

What was the key to Jesus’ love in the face of such injustice and persecution that, if we experienced it, would move every fiber of our being toward bitterness and vengeance? It’s found in v. 23: Jesus continued entrusting himself to him who judges justly. Just as Paul made clear in Romans 12:19, God the Father is a just judge. He will right every injustice. He will repay all the wrongs to you by your enemies. Vengeance is his. Trusting the Father is the example Jesus offers us. On top of that, the injustices Jesus suffered far outweigh any we do because he is the sinless Son of God. And yet, Jesus still entrusted himself to his Father.

Only the Son of God could know this way, and he has showed it to us. We of course could not know this way because in our sin we are not sons who would be inclined to trust God the Father. Romans 12:19 reveals that as well. Our bitterness and desire for vengeance springs from our lack of trust in God to act justly. In our sin we see God as a stranger and enemy. In our sin, we are his enemies. And this is where Jesus the Son of God proves to be more than just a model and an example for us. Jesus proves to be a savior and a son-making brother. Consider what Peter follows up his illustration of Jesus our example with in 1 Peter 2:24,

He himself bore our sins in his body on the tree, that we might die to sin and live to righteousness. By his wounds you have been healed. For you were straying like sheep, but have now returned to the Shepherd and Overseer of your souls (1 Peter 2:24–25)

Peter follows up Jesus our example with Jesus our savior. We, sinful man, were straying sheep in need of a seeking-shepherd. We were wounded by our own sin and in need of a healer. We were dying from the curse in need of a savior. And, in the heat of our fully bloomed sinful bitterness toward God and our fellow-man, we killed the Son of God.

And Jesus did not become bitter toward us but prayed for us even when we persecuted him to death,

And Jesus said, “Father, forgive them, for they know not what they do” (Luke 23:34)

And Jesus rather than seeking vengeance entrusted himself to his Father,

Then Jesus, calling out with a loud voice, said, “Father, into your hands I commit my spirit!” And having said this he breathed his last (Luke 23:47)

And by doing these things—by fulfilling the very command in Matthew 5:34 that he laid before lost, sinful, embittered men who were not sons of God but enemies of him—Jesus bore our sins in his body that we might die to sin and live to righteousness; Jesus healed us; Jesus chased us down like a shepherd seeks out his straying sheep to return us to God the Father. Jesus the Son of God saved us and made us sons of God again (Romans 8:14–17) because he did not become bitter toward us, his enemies.

So how do we overcome sneaky, insidious bitterness that would threaten to bloom to the harm of others and the eternal harm of ourselves? In Jesus the Son of God, we have been given the example to follow. We entrust ourselves to God the Father to do right. And we can do this, because in Jesus the Son of God we are no longer sin-enslaved enemies of the Father who distrust him with our lives. Rather, Jesus the Son has made us sons with him—sons who know and trust the Father, and who are able to follow in the way that Jesus has showed us.