I vaguely remember confusing these guys as a kid too, and even the first few times I read this post thought Sy was right until I realized David was OT and Jesus was NT, so they had to be different guys. Then I looked them up on Wikipedia to disambiguate.

I think one of the things that confused me as a Catholic too is the way readings are done at mass. They’ll pick a gospel from the NT and first and second readings usually but not always from the OT that all go together THEMATICALLY, but you’re not reading the stories as CHRONOLOGICAL accounts. Unless you read the bible cover to cover on your own(which I’ve only done maybe twice), it’s hard to see where all the disparate stories fall into place. I think the first time I read it on my own was actually when I cleared up my own Saul confusion. Then I forgot about it for 23 years until I read this post.

You may need to remind me again in a few decades. :)