Which part? The part about the saints? No, I got that from reading the New Testament.
The NT usually refers to all believers as saints. I'm not going to just give a list of verses but here is one example:
Ac
9:32 Now as Peter was traveling around from place to place, he also came down to the saints who lived in Lydda.
"Saints" in the NT is just one way of the Church refering to themselves. They weren't called "Christians" until after some time:
Acts
11:26 ..... Now it was in Antioch that the disciples were first called Christians.
No, we have standing armies today too.