But now that you’ve come to know God—or, better, to be known by God—how can you turn back again to that weak and poverty-stricken lineup of elements that you want to serve all over again?
In kindergarten, you learn the basics upon which you build for later learning and living. It is necessary, but not where anyone in their right mind desires to stay.
This is the analogy Paul is making for us with regard to the Law of Moses*. It’s necessary to learn those basics, but that was all for something much better, more complete, to come later.
To stay tied down to the rules, even to morals, is to stay in spiritual kindergarten, and really gets you nowhere as far as growth. This is where you see damage inflicted by strict fundamentalism which misses the point of it all. When you’re obsessed with what everybody shouldn’t be doing, there’s little room left to enjoy God as the son or daughter Jesus made you to be since the cross, since the outpouring of His Spirit.
Paul is saying, “Since you’ve been enlightened by Christ, and given His Spirit to live on, in, and through, why on earth would you ever go back to the way it was before, keeping up with a bunch of rules and rituals in order to garner favor with God??”
I think it is always more powerful to point to who we are rather the what we should do.
When you really accept who you truly are in Christ, you’ll do what you need to do.
*Paul could also be referring to all religious thought before Christ—worshipping the elements such as fire, air, sun, moon, etc. and obeying/sacrificing in order to appease God or the gods.