Albert Barnes on Colossians 2:17

Which are a shadow of things to come. Heb 8:5. Heb 10:1 They were only a dim outline of future things, not the reality.

But the body is of Christ. The reality, the substance. All that they signified is of or in Christ. Between those things themselves which are in Christ, and those which only represented or prefigured them, there is as much difference as there is between a body and a shadow--a solid substance and a mere outline. Having now, therefore, the thing itself, the shadow can be to us of no value; and that having come which was prefigured, that which was designed merely to represent it, is no longer binding.

(c) "shadow of things" Heb 8:5