I will! If the priest must celebrate Mass - perhaps he is the only priest, whatever - he must also consume both the Body and the Blood of Christ. This is required.
So, what does he do? If he finds himself in this unfortunate state, he must make as perfect an act of contrition as he can, firmly determined to get to confession as fast as possible, and then celebrate Mass.
I would hope that before that day ends he will have been able to meet with another priest and make his confession.
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