In 2 Corinthians 3:14, Paul is explaining the contrast between the fading glory of the ministry of the old covenant (law) and the everlasting glory found in the new covenant (Christ).
He explains how the veil remains and hearts remain hardened when the law is read. This isn’t simply talking about the act of reading, but really about the upholding, study, and overall meditation and adherence to the law without understanding its purpose of pointing to Christ, through whom we have a much more excellent covenant.
It is important to understand no one gains this knowledge on their own, we can’t remove our own veil, only through Christ can we gain proper understanding and see the full glory in the new covenant. This chapter was instrumental in helping me understand the message of the new covenant and also helped to keep me humble by realizing that only by His Spirit am I able to comprehend the glory of His covenant.
It’s easy to forget that any knowledge we have about Christ is a gift, so when He makes something understandable it’s tempting for us to get frustrated when others can’t see it. This scripture serves as a reminder that we are not the ones who reveal or open the hearts of anyone, but that we should be faithful in sharing the truth of Christ and let His Spirit do the rest.