1 Corinthians 11:27

'Wherefore whoever shall eat the bread or drink the cup of the Lord in an unworthy manner, shall be guilty of the body and the blood of the Lord.'

This being so what a great sin it is that men participate in the Lord's Supper in anything but the most genuine way, and without the most serious of thoughts. Especially that they participate in a spirit of disunity. By doing so they are trifling with the cross, are guilty of His death because they treat it lightly, and are as it were crucifying Him afresh to no purpose (compare Hebrews 10:29; Hebrews 6:6). And this is precisely what the Corinthians were in danger of doing, for they were openly negating one aspect of what He had come to do, the uniting in one in full equality of all who are His. And many of them were also approaching Him in a casual spirit.

'In an unworthy manner.' In context this means casually, both in casualness of spirit (being merry) and in sinful disharmony and with sinful discrimination (being in disunity), without regard for what the Lord's Supper represents. This does not refer to our not sufficiently appreciating what we are participating in, for none of us ever do that, nor does it refer to our not being in a state of total worthiness, for we never are although we should seek to be. Our total worthiness is rather in Christ. So it rather means not approaching participation in a totally casual way, which includes in this case overt disunity and lack of brotherly love, with the result that participation has become a meaningless exercise, trivialised and lost in other excesses.