Did you try spraying starting fluid into the throttle body and crank it to see if it will fire up? That can help narrow it down to fuel or spark.
Also get a decent code reader. You can borrow one from most any parts store, or got one from Amazon. That piece of equipment will be your most used tool. Once you have the codes it will pretty much tell you whatever ails your vehicles.
Put a fuel pressure gauge on the fuel rail at the Schrader valve and see what pressure you are getting. Should be (IIRC) 55 psi. 50 minimum. And put a tester on each individual plug wire to be certain each plug is firing.
Now, what is the last thing or two that you did to the Jeep before this started? Could be as simple as a ground wire got knocked or corroded too much.
All these things will help us get you going again. They are all easy tests that can be done in a few minutes.