things to them, and give up

For personal reasons, thinking about the word "sacrifice". For a believer, you would think the act of sacrifice to be an easy thing. All pales in comparison to Calvary, and the believer that reflects on it each month at the Lord's Table is reminded of the significance and extent of the sacrifice made by Christ.

And yet when it comes to sacrifice, why is it still so difficult? For someone who adores the Lord's Table, who gets choked up regularly at the mention of the cross, why is it still so difficult to part with something anything whose cost is no small matter?

If selfishness has roots so deep within the believer, what must it be like in the unbeliever?