What does it mean if someone says "I say this by concession, not command"?

It is not reliable to ask people to tell you what the bible says. Many people will make up stuff because they don't know what it says, and many will make up stuff because they wish it would not say what it says. You just have to read it for yourself. Read a chapter of Proverbs every day. Proverbs has 31 chapters so you can keep your place by just looking at a calendar. There is no religion or nothing in Proverbs and you don't have to believe anything. Just read every day. When you are comfortable with that, then read the bible from Romans to 2 Thessalonians over and over until you start to remember what it says. That is the part that applies to Christians.

When you don't understand something, keep reading. It is usually explained. When that doesn't work, write your question on a paper and put it in a safe place. I used to pin them to the wall near the ceiling so they wouldn't get knocked down, but now I keep them in a box in my desk. Eventually God will send understanding, and then you can retire that paper.