Legalism in the Bible is different than you have been taught.
"Legalism" has come to mean almost anything somebody does not want to do. Paul had one specific fight in mind, and it was not about whether Christians obey.
The smallest word in the New Testament is the one nobody preaches.
Colossians, First Corinthians, Hebrews, and John all hang an "if" on the promise. Here is what they hang it on, and what real assurance actually stands on.
Once saved, always saved' rests on three verses. Not one of them is about you.
John 10:28, Romans 8:38-39, and Ephesians 1:13-14 are the strongest security texts in the Bible. Read all three closely and every one of them is guarding the same door, and it is not the door most people assume.
Sinners Prayer? 3000 people asked what to do. Peter never mentioned a prayer.
Acts 2 is the first gospel sermon ever preached and the first conversion ever recorded. Read what Peter told them to do, then read what they had done before the sun went down.
The most famous evangelism verse in the world was never about evangelism.
Revelation 3:20 has an address line on it, and the address is a church. The man behind that door already carries Christ's name, and the sentence right before the knocking calls him a son.
Paul said confess with your mouth. That is not something you do in private.
Romans 10:9 is the most quoted conversion verse in the Bible and the most truncated. Read the chapter it actually lives in and Paul explains why it’s been used wrong.
Jesus did not say worship however you feel. He said worship in spirit AND truth.
John 4:24 is the most quoted and least obeyed verse about worship. Spirit without truth is emotionalism. Truth without spirit is formalism. Jesus demanded both.
When the church reads Scripture together, it is not a Bible class. It is an act of worship.
The New Testament treats the public reading and teaching of God's word as worship. Paul gave Timothy three commands: read it, explain it, urge people to live it. All three are acts of worship.
The Lord's Supper is not a ritual. It is a proclamation. And the early church did it every Sunday.
Most churches take communion monthly or quarterly. The New Testament church broke bread every first day of the week. The Greek tells you why it mattered that much.
Prayer in the New Testament is an act of worship. Your church probably treats it as an intermission.
The early church devoted themselves to prayer as a central act of worship. Today most churches squeeze it between the songs and the sermon. The Greek tells you why that matters.