He was well aware what the Lord expected him to bring to the altar as a sacrifice.
Pride and jealousy seemed to be a huge factor.
He may have had the most beautiful, plump, luscious fruits and veggies. They were probably the best imagined - bright and beautiful, flavorful and delicious. It may have been the best crop ever harvested. BUT - there was a problem with this marvelous fruit.
That is not what the Lord told Cain to bring Him.
The Lord provided all that Cain had - the perfect crops as well as the animals.
How many times have we done the same.
He provides so much for us.
There are times He lays something specific on our heart that He wants us to sacrifice for him.
It might be that He wants us to sacrifice some time for Him.
We may respond - oh no Lord, I just don't have time to do that for you, or to spend with you, etc - but, I have all this money - I will just give more.
It might be the opposite - He may be saying - I want you to give $____ for this need. - and we may be saying - I am so good at that, or I will do it, I just don't have the money - You know I have this bill or that thing coming up - I just don't have the extra.
He may have given us a talent...singing, art, technology, teaching, preaching, praying, etc. He may have told you - I would like you to bring that "sacrifice" of the talent I gave you but something may be stopping you. Sometimes it is fear, pride, selfishness or jealousy that prevents us from acting.
There are times we bring the wrong sacrifice to the altar or don't bring one at all.
I know I need to pray about this - I want that thing I give up to be something the Lord wants and will accept. How sad is it when we are doing what WE think is best and actually giving up at times for naught, when if we just listened and did what HE wanted the results would be incredibly amazing.
The definition of sacrifice is an act of offering to a diety something precious.
Praying to know that precious thing He wants from me and you