In our last few studies of 1 John 2:28-3:10, we celebrated the glorious truth that God loves us so much that He decided to call all believers His children. John wrote: "See what kind of love the Father has given to us, that we should be called children of God; and so we are." (1 John 3:1, ESV).

In this next passage, 1 John 3:11-18, we have a much more difficult truth to digest. It's this: If God has made us into His spiritual family, we must love our spiritual siblings. Last week, you may have celebrated God's love for you, but you must struggle to show your love for others. This passage gives us practical help on how to demonstrate Christian love.

Remember, though, John's three tests. He's introduced all of them already and will revisit them throughout the rest of his letter.

1. Do I believe in Jesus?
2. Do I obey God?
3. Do I love God's people?

And, today, John will address the third test. He will talk to us about love. From the passage, I am going to draw out seven lessons on how to love, especially how to love God's people. Today, we will look at the first two of these lessons.

1. Be aware of the temptation to neglect love (11-12).

11 For this is the message that you have heard from the beginning, that we should love one another. 12a We should not be like Cain, who was of the evil one and murdered his brother.

The Message: Love

John starts this section by reminding us of the message that we heard from the beginning (11). When Jesus came into your life, when you looked at the cross, you realized His love for you. But you also should have noticed His love for the people of the world. Then, after your conversion, you should have heard Him urge you on to a life of love.

"A new commandment I give to you, that you love one another: just as I have loved you, you also are to love one another." (John 13:34, ESV).

A Negative Example: Cain

But we are often tempted to neglect love.

I wanted this point to be: "Be aware of the temptation to hate." The word hate, though, makes me think of an intense dislike.

But the passage, though it includes intense dislike, will show us a lovelessness on two extremes. At one extreme, neglect of love is manifested in murder. At the other extreme, neglect of love is manifested in indifference. It's not just intense dislike John is referring to, but a full spectrum of a refusal to love.

And Cain stands out as an excellent prototype of lovelessness (12). If you're not familiar with his story, allow me to introduce you. He was one of Adam and Eve's children. He had a brother named Abel. Their parents urged them to worship God, and one day, they both offered sacrifices to Him. Since Cain was a farmer, he offered up some "fruit of the ground" (Genesis 4:3), and since Abel was a rancher, he gave "the firstborn of his flock" (Genesis 4:4). God regarded the sacrifice of Abel, "but for Cain and his offering He had no regard" (Genesis 4:5).

What made their sacrifices different? Why did God receive Abel's and reject Cain's? People propose many theories, but Hebrews gives us insight:

"By faith Abel offered to God a more acceptable sacrifice than Cain..." (Hebrews 11:4, ESV).

Abel's sacrifice was one of faith. Cain's was not. And what is the opposite of a faith sacrifice? One of works. Cain was arrogant enough to think he could earn God's favor.

God's rejection of Cain's sacrifice was meant to instruct him (and all of us) to approach God by faith. Instead, it enraged him. He wanted to kill Abel. A poison was released in his inner being. His soul was infected.

And God pleaded with him:

"The Lord said to Cain, 'Why are you angry, and why has your face fallen? If you do well, will you not be accepted? And if you do not do well, sin is crouching at the door. Its desire is contrary to you, but you must rule over it.'" (Genesis 4:6–7, ESV).

Instead of heading God's warning, however, Cain blew right through it and committed the first murder.

And before we move on into learning why Cain killed Abel, we must consider the process he went through. God told him sin was crouching at the door. Cain was tempted by the evil one, a clear reference to the devil (12). He tempted Cain to hate Abel, to slaughter (the Greek word) him.

And Cain was not oblivious to the temptation. God showed him sin was crouching at the door.

We should not be oblivious either. The temptation to neglect love is ready to pounce.

I remember years ago when I was a crazy youth pastor, another pastor and I had a friendly rivalry. He was the church's worship leader, and because of our duties, we would often arrive at the church campus while it was still dark on Sunday mornings. Our custom was to try to startle the other. We'd slap each other's windows, quietly sneak up on each other, or stand behind a corner waiting to scare the other.

One Sunday, I decided to put an end to it all. I arrived early but parked where he was sure to miss my car. I came into the office, locked everything behind me as if no one was there, and when I saw his headlights pulling into the parking lot, I set the alarm as a way to make him think no one was in the building. After that, I stood on a countertop, in the dark, right next to his office door. He never saw it coming. As he rattled his keys to open his office below me, I let out the most blood-curdling banshee-like scream I could muster. Thankfully, he survived the heart attack. He then communicated that he'd like our little game to stop.

But while our game was on, I grew to become alert whenever walking onto the premises. I was ready. And it's this type of readiness we must have concerning the temptation to lovelessness. All around us, opportunities to neglect love abound, even at church!

The parking lot is full of cars with people eager to worship God, but I'm angry I have to park far away. The Calvary Kid's teacher who arrived early and attended training to volunteer to serve my kids didn't pay as much attention to my child as I'd like, so I'm upset. An usher didn't smile at me. A pastor didn't shake my hand. And someone is sitting in my seat!

And if you give yourself to a local church or anybody in Christ, you'll find a million opportunities to take offense or grow indifferent. The temptation is real. Like Cain, sin is crouching at the door. But rather than give in to outrage or detachment, stop and realize the tempter of your soul is trying to get you to neglect love.

2. Be alert concerning your potential for jealousy (12).

12b And why did he murder him? Because his own deeds were evil and his brother's righteous.

John continued using Cain as an example by asking a straightforward question: And why did he murder him? (12). Why did Cain kill Abel?

The answer: Because his own deeds were evil and his brother's righteous (12). Cain was jealous of Abel. He saw the favor God gave his brother and hated him for it. In seeing Abel, Cain saw himself. He knew his brother was a good and righteous man. He saw God blessing him. It enraged Cain. And jealousy swelled in his heart.

But instead of learning from Abel's life, Cain lashed out at Abel's life.

This is often how it is in the body of Christ. We can quickly become jealous of others, especially those who are righteous and favored by God.

John touched a sensitive nerve here, since hatred toward another Christian is often prompted by a feeling of guilt about one's own life as compared with that person's. -- John F. Walvoord and Roy B. Zuck, The Bible Knowledge Commentary, 896.

The religious leaders were jealous of Jesus, so they killed Him. The elders and scribes were jealous of Stephen, so they killed him. Saul was jealous of the early believers, so he persecuted them.

And this potential to lash out against other believers because of jealousy resides in all of us. One churchgoer sees the genuine and happy marriage of other members, and begins to despise them for their joy, or begins despising all marriages. Another member witnesses the professional skill and advancement of another, and grows jealous of their success. Or someone sees God using the life of another, perhaps in a way they'd like to be used, and soon they are looking for any excuse to tear down the other.

I think parents do this often. They see a happy family or respectful children, and immediately begin making excuses about how it came to be. And they also excuse their own situation as mere chance or misfortune. Rather than rejoice at the blessings another has received from God - or try to learn from a healthy family - some parents' first move is often to tear down the other.

But it's not just parents who engage in this brand of jealousy. Believers of all types can trend towards jealousy of others, and it manifests itself in ugly ways. If a church isn't careful, all kinds of battles will break out. Singles vs. Marrieds, Old vs. Young, Men vs. Women, Pastors vs. the congregation, Rich vs. Poor.

We should instead "rejoice with those who rejoice [and] weep with those who weep" (Romans 12:15), and remember, every time we set foot on the church campus, attend our Life Group, or open up Instagram, that the potential for jealousy is in us all.