John 8:31-32

I think the reason John made sure we knew that Jesus was talking to people who believed in Him, is because of the verses before. In verses 12-19 Jesus proclaims truth about who He is. Verses 21-30 are about Jesus warning unbelievers. So, He introduces Himself, warns unbelievers, then tells believers if they remain faithful to His teachings, they will know the truth and the truth will set them free.

This freedom is tied to truth. The truth is about who Jesus is, what He did, and what He taught. I also think this is about sinners becoming saved as well as believers not turning to legalism. A lot of Jesus's interactions with the Sadducees and the Pharisees was Him trying to tell them they were legalistic. God gave 10 Commandments. They added over 600 more rules that they held people to. Those weren't from God. Jesus wants us to be free and live by His teachings. I forget that sometimes!