1 Corinthians 6:12 All things are lawful unto me, but all things are not expedient: all things are lawful for me, but I will not be brought under the power of any."Christian liberty" is freedom from the bondage of sin and the work of trying on your own. Everyone who is saved and formerly bound by sin is set free. Jesus paid the price for all our sins. He redeemed us, or one way to look at it, we were bound in slavery, but he bought our freedom! The payment was made in blood and by his death. He did that for us because our own blood is not payment enough. Our blood belongs to God anyhow, so there is no way to give God what already belongs to him!
1 Corinthians 10:23 All things are lawful for me, but all things are not expedient: all things are lawful for me, but all things edify not.
Galatians 5:1 "Stand fast therefore in the liberty wherewith Christ hath made us free, and be not entangled again with the yoke of bondage."There are two types of slavery: to sin and to The Law . Actually scripture speaks more harshly of dotting the i's and crossing the t's in keeping the Mosaic Law, which is the commandments and all the regulations associated with them. The problem with slavery to sin is that it separates the person from God. The problem with keepers of The Law is that they are striving to please God without loving God or anyone else for that matter!
With salvation we are totally free of Mosaic Law. Dietary rules, ceremonial cleansing, ritual worship, animal sacrifices and the like are no longer required! In fact to do those things in trade for righteousness is viperous! We're no better than snakes! Obeying commands BECAUSE we love God is what God desires. Don't get "Christian Liberty" confused. We are free to ignore laws, but because we're saved, we should never want to disobey any command! Rather than being metrics for punishment they are standards for love!
So obeying The Law isn't necessary for Paul (nor us), but it is "expedient", or, i.e., can be beneficial! The most expediency for obedience is as a demonstration of our love of God, but we get the bonus because we get some type of "crown" for our obedience!
Likewise, some things just don't "edify" or other words, don't enhance the mind or build character for the self, nor improve our standing with God. As subjects of the King, we are to "tend the royal garden". We are to make the kingdom of God a beautiful place. It's holy ground and we are to sew seeds of salvation and grow majestic disciples of Christ!
Some things which are not lawful, but we do anyhow, causes guilt on our part and disappoints God Edifying God is lifting him up! We can't lift him up by putting him down!