How is the following verse to be interpreted in context, since we know the Lord Jesus Christ is not the Holy Spirit, and vice versa, as per Catholic teaching and more specifically per the St. Athanasius Creed.
Now the Lord is the Spirit, and where the Spirit of the Lord is, there is freedom. - 2 Corinthians 3:17
The simple answer is: God is the “Lord,” and the Holy Spirit is the “Lord.” I don’t think you should assume that the reference to the “Lord” here automatically means “the Son is the same person of the Trinity as the Spirit.”
The answer is in the context. St. Paul is talking about the interpretation of the Law. The Jews interpret the Law to the letter, but they miss the spirit behind the Law. Christ is the spirit of the Law and the rule for interpreting it. Reread the passage with that in mind and see if it makes more sense.
Remember that the capitalization of “Spirit” is an editorial choice (perhaps misguided) for the English translation. It does not mean that Paul is necessarily talking about the Third Person of the Holy Trinity.
I don’t think he’s speaking about Christ’s spirit literally, but that Christ is the “spirit of interpretation,” which simply means that we ought to read Scripture in a Christocentric way. I think this is the plain and most literal reading of Paul’s words, not that I mean to exclude other secondary senses.
So “spirit of interpretation”, but not Christ’s Spirit… those seem to be very close to being one and the same, since it seems the former comes from the latter. What does Christocentric mean, you mean read scripture as Christ always being the main focus?
Just to add to what has been said: if you look more closely at the beginning of the chapter (especially vv.2-4) you can see that Paul is setting up some distinctions between Christ, God (the Father) and the Spirit.