en_tn_condensed/1sa/14/33.md

by eating with the blood

"by eating meat without draining the blood first as required by the law"

You have acted unfaithfully

Saul is accusing his whole army of acting unfaithfully though this is a generalization.

Now, roll a big stone here to me

The stone would hold the animals up and make it easier to drain the blood from them.