John Gill Commentary 1 Samuel 14:33

"Then they told Saul, saying, Behold, the people sin against Jehovah, in that they eat with the blood. And he said, ye have dealt treacherously: roll a great stone unto me this day." — 1 Samuel 14:33 (ASV)

Then they told Saul
Some that were more conscientious and religious, were more circumspect, and strictly attended to the laws forbidding the eating of blood, and were concerned at the indecent behaviour of others, and therefore thought fit to acquaint Saul with it, to restrain it:

behold, the people sin against the Lord, in that they eat with the
blood ;
by breaking the laws of God respecting the eating of blood in (Genesis 9:4) (Leviticus 3:17) (Leviticus 7:26Leviticus 7:27) (Leviticus 17:10Leviticus 17:11) , especially in (Leviticus 19:26)

and he said, you have transgressed ;
the above laws of God; that is, Saul said to some persons who were accused of the breach of them, and were ordered to come before him, and did come:

roll a great stone unto me this day ;
pointing, perhaps, at one which lay at some distance from him, and which he ordered to be rolled to him; this was done, that the creatures might be slain on it, and their blood drawn out from them, or to offer sacrifice upon, and indeed for both.