We know from the Word of God that the ways of the flesh and the ways of the Spirit cannot be reconciled. They are mortal enemies, and can be nothing but mortal enemies. As long as God is holy, and as long as sin is filthy, the two will be at odds, that is to say, they will be at odds everlastingly. Paul pictures this in Corinthians as a matter of eating at one of two tables. You may not, he says, partake of the table of demons and the table of the Lord. One may physically do it, certainly, but such a one may also physically die or get seriously ill.
The antithesis between good and evil extends into everything, and this antithesis is marked by how we eat and drink. The point is not that you may not eat here if you have sinned at all (for all sin is in some manner partaking of what the devil has cooked for you). The point is that you must not eat here with the formed and settled intention of continuing to eat from both tables. That is high-handed arrogance, of the kind that God strikes.
But of course, the point of such warnings is not to chase you from the Lord’s Table. Realize the force of the argument here. If you are baptized, and have not been lawfully excommunicated from the Church, then you are not just invited to come and partake. Rather, we insist that You come, and we do not do this on our own authority. The Lord of the Table, the Lord Jesus, insists that You come to Him, and partake with Him, and in Him. If you are baptized, you must come.
At the same time, you may not deliberately partake of both tables. And this means that there is only one real option for you. If you are clutching to any known sin, you are not just invited to repent, or asked to repent. Rather, this solemn and joyful moment constitutes a command that you repent.
Bread in hand, the name of this sin that must be forsaken is the sin of divided loyalties. Garden variety sins are confessed in the first part of the service. Divided loyalties need to be dealt with here.