Summary: verse by verse through Acts
If you were to ask most people what they think is the greatest thing about being an American, they’d probably say that the best thing about being an American is having freedom. We love living in the United States because here we are free. Being an American citizen means we are politically free.
Now, if you were to ask most people what they think the best thing about being a Christian is, you’d probably get a plethora of answers. The best thing about being a Christian is that I’m going to Heaven. The best thing about being a Christian is that I can talk to God. The best thing about being a Christian is that I’m now happy. The best thing about being a Christian is that I have true friends in the church.
While all those answers are good and valid, the underlying reason why it’s so great to be a Christian is that we are now spiritually free! And that spiritual freedom produces all those results that we so enjoy in the Christian life. As a Christian, we have that  freedom in Christ that gives us the life we so enjoy.
Because of Christ we are now free from the eternal penalty of sin.
Because of Christ we are now free from sin’s bondage over our daily lives.
Because of Christ we are now free to approach God with our prayers.
Because of Christ we are now free to have a relationship with our Creator.
Because of Christ we are now free to live as we were created to live.
Because of Christ we are now free to worship God as an individual.
It is great to be a Christian because now I am spiritually free!
But there are those who would seek to take away that freedom in Christ. Those people who think they have the corner market on spirituality and have appointed themselves the fourth person of the trinity here to set us straight. Today we’re talking about how legalism seeks to take away the most precious thing we have as Christians – our freedom.
Now just what is legalism? Legalism is when you try to add rules and stipulations to a person’s salvation. A legalistic person would say that the salvation of the soul is by Jesus plus adhering to this rule and that rule. You’re saved by Jesus and works – not just Jesus.
A legalistic person would also say that maintaining that salvation is based on adhering to a strict set of rules that are usually preference-based and not bible-based.
In both cases, your spirituality becomes a very self-righteous endeavor of rigid rules that enslave a person. The freedom and joy in Christ disappear and bondage returns.
Not only is legalism ungodly and unbiblical,  legalism causes disunity. Wherever you see legalism being allowed to fester, disunity will surely follow. And that’s what happened in the early church some 2,000 years ago. Turn with me to Acts chapter fifteen where we see people try and introduce legalism into the early church.
[Read Acts 15:1-6.]
Remember, throughout Paul and Barnabas’ missionary travels, thousands of Gentiles were turning to Christ. Just like in Peter’s ministry, it was obvious that God was working amongst the Jews and non-Jews in the same way. God was not a respecter of persons and He would save whoever would come to Him by faith.
But there were some legalistic Pharisees in the church who still had some bias against the non-Jewish community and expected them to act like Jews when they became Christians.
In verse one they said that they needed to be circumcised to be saved. (Adding works to salvation.)
[Read Acts 15:1.]
In verse 5 they implied that these Gentile Christians needed to follow the Mosaic law after being saved. (Substituting self-righteousness for God’s leadership in a person’s life.)
[Read Acts 15:5.]
Either way you slice it, these legalists wanted everyone to live the way that they lived and were causing great disunity in the church.
You see, these people probably never understood what the Mosaic law was all about. Living by the Old Testament law was never the means to salvation. It was always the tool that the Lord used to show people their need for salvation. Since it’s impossible for us humans to even uphold just the ten commandments, the law shows us that we need a Savior. All through the Old Testament the Lord promised to bring a Savior who would save us from our sins. Trusting in His promise, and trusting the Savior once He came, is our salvation. Not living by the law.
People who don’t understand this can fall into the trap of legalism, and it’s a trap that can cause disunity in the church.
[Swindoll ‘missionary and peanut butter’ story from his book “Grace Awakening”.]