1993 Jeep YJ Car not starting

I just got my 1993 Jeep Wrangler YJ. It worked perfectly fine for about two weeks now, but every so often the battery would seem weak when starting up. Took awhile for it to roar to life.

Then this morning, I went to start it, and it just clicked. It didnt even try to turn over. I tried it several times then gave up. I charged the battery all afternoon so it was at 100%. Still nothing. I then tried to jump it with another truck. Still nothing. So the battery had enough juice to start, but something else was preventing it from doing it. I then cleaned the heads of the battery so that they were sparkiling clean. Tried again. Once the motor turned over, but that was the only action. Again tried to jump start it, it still only clicked.

I need a solution to this problem becuase I would really like to drive my new jeep that I just spent all my money on. Please help, thank you