Before you can answer "Is this right or wrong?", you have to answer a bigger question: who gets to decide? Get that one right, and most of the rest falls into place.
Who gets to decide?
Is truth objective, or is it subjective? Does truth change? Is it my truth and your truth, or is there simply THE TRUTH? Some people say there's no one truth. But you have to ask, is that true? They just told you there's no one truth and claimed it was true.
The struggle people have with truth is that, by its very nature, it's divisive. It draws a line in the sand. It says, "On this side is right, and on that side is wrong." We really only have four options for who gets to draw that line:
I get to decide. When my daughter Hope was about six, she looked at me and said, "Dad, do you know that I know everything?" Like any pastor, I had to correct her theology: "Sweetheart, you don't know everything. Only Jesus knows everything." And she wept. So I did what any man does when a woman is crying. I changed the subject. "Look outside, baby. There are some trees. You want some cookies?" It's a silly story, but how insane is it to think we get to determine truth? I know me, and I wouldn't trust me with truth.
Society gets to decide. Society is always changing. If 51% agree, does that make it right? What happens when that 51% changes its mind in four years? Slavery was a socially acceptable part of life for almost all of human history.
My family gets to decide. Would you trust your family with truth? You know your uncle. He's drunk at Thanksgiving every year. He's my boy, but I'm not letting Uncle Ted watch my kids, and I'm definitely not trusting him to determine right and wrong.
God gets to decide. I'm simple. If there's a God so powerful He speaks and universes appear, who then steps into human history, lives a sinless life, says He's going to die and rise three days later, and pulls it off, I'm on His team. Maybe His ways are higher than my ways (Isaiah 55:9). Maybe if You created me, You get to tell me what's right and wrong.
It's the oldest question in the world
This fight started in the Garden. The serpent asked Eve, "Did God really say you must not eat the fruit from any of the trees in the garden?" (Genesis 3:1 NLT). Surely God didn't mean that. Or maybe He's holding out on you.
The deception of Eve is the deception of us all. Is it really wrong to tell that lie? Is it really wrong to look at that person with lust as long as I don't touch? Is it really wrong to divorce my spouse? The battle over what's right and wrong is really a battle over what's true and what's a lie.
Jesus is the standard
Jesus said, "I am the way, and the truth, and the life" (John 14:6 ESV). "The way" means the way to live. Jesus shows us what a life that pleases God looks like: how He loved people, how He forgave people, even how He rebuked people. He's the bullseye.
The Bible's word for missing that bullseye is sin. And here's what our culture does: instead of admitting we've missed the mark, we've moved the target. But just because I don't like the standard doesn't mean I get to change it. "There is a way that seems right to a man, but its end is the way to death" (Proverbs 14:12 ESV). As followers of Jesus, we don't get to set the standard. We're simply responsible for following it.
So how do I actually know?
If Jesus gets to decide, then I need to know Him and His Word really well. Here's how that plays out:
Start with what God has clearly said. "All Scripture is inspired by God and is useful to teach us what is true and to make us realize what is wrong in our lives" (2 Timothy 3:16 NLT). If God's Word clearly calls something sin, it's settled, even when culture says otherwise.
When the Bible doesn't name it, look for the principles. The Bible doesn't mention vaping, video games or most of what's on your phone. For gray areas, ask: Am I honoring the authorities God has put over me? (Romans 13:1). Will this control me? "'All things are lawful for me,' but I will not be dominated by anything" (1 Corinthians 6:12 ESV). Will it cause someone else to stumble? (Romans 14:21). Can I do it to the glory of God? (1 Corinthians 10:31). For an example of how this works, read Can Christians Drink Alcohol?
Ask a better question. The question isn't "Can I do this and still be a Christian?" It's "Is this pulling me toward Jesus or away from Him?"
Listen to the Holy Spirit. Jesus said the Spirit "will guide you into all the truth" (John 16:13 ESV). The Spirit will never lead you against God's Word, but He will nudge your conscience. If you can't do something with a clear conscience, don't do it. "For whatever does not proceed from faith is sin" (Romans 14:23 ESV).
Ask people who know God and know you. "Without counsel plans fail, but with many advisers they succeed" (Proverbs 15:22 ESV).
You might be thinking, "Who are you to judge?" Fair question. I'm not trying to be anyone's judge. A person who repeats the Word of God isn't a judge. He's a messenger. I'm under the same standard you are, and I miss the mark too.
Why it matters
The battle over truth is the battle over your eternity and your freedom. "You will know the truth, and the truth will set you free" (John 8:32 ESV). Every lie you believe is a chain you carry. God's standard isn't there to steal your joy. God is not in the way of your happiness; He is the way to your happiness.
Scripture: Genesis 3:1–6; Isaiah 55:8–9; Proverbs 14:12; 15:22; John 8:32; 14:6; 16:13; Romans 13:1; 14:21–23; 1 Corinthians 6:12; 10:31; 2 Timothy 3:16–17