For he that eateth and drinketh unworthily, eateth and drinketh damnation to himself, not discerning the Lord’s body. 1 Corinthians 11:29

I believe there ought to be a preparation before the Lord’s Supper. I do not believe in Mrs. Toogood’s preparation, who spent a week in preparing, and then finding it was not the Ordinance Sunday, she said she had lost all the week. I do not believe in that kind of preparation, but I do believe in a holy preparation for the Lord’s Supper: when we can on a Saturday if possible, spend an hour in quiet meditation on Christ, and the passion of Jesus; when, especially on the Sabbath afternoon, we can devoutly sit down and behold Him, then these scenes become realities, and not mockeries, as they are to some. I fear greatly that there are some of you who will drink the wine, and not think of His blood: and vile hypocrites you will be while you do it. Take heed to yourselves, “He that eateth and drinketh” unworthily, eateth and drinketh-what?-“damnation to himself.” This is a plain English word; mind what you are doing! Do not do it carelessly; for of all the sacred things on earth, it is the most solemn.  Here you are to drink blood from the veins of Christ, and sip the trickling stream which gushed from His own loving heart. Is not that a solemn thing? Ought anybody to trifle with it? To go to church and take it for sixpence? To come and join us for the sake of getting charities? Out upon it! It is an awful blasphemy against Almighty God; and amongst the damned in hell, those shall be among the most accursed who dared thus to mock the holy ordinance of God. This is the remembrance of Christ. “This do in remembrance of Me.” If you cannot do it in remembrance of Christ, I beseech you, as you love your souls, do not do it at all. Oh! unregenerate man or woman, enter not into the court of the priests, lest Israel’s God resent the intrusion. ~C.H. Spurgeon

http://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0002.cfm