We must, therefore, make a distinction here among men. For those who are wanton and dissolute must be told to stay away; for they are not prepared to receive forgiveness of sin, since they do not desire it and do not wish to be godly. But the others, who are not such callous and wicked people, and desire to be godly, must not absent themselves, even though otherwise they be feeble and full of infirmities, as St. Hilary also has said: If any one have not committed sin for which he can rightly be put out of the congregation and esteemed as no Christian, he ought not stay away from the Sacrament, lest he may deprive himself of life. For no one will make such progress that he will not retain many daily infirmities in flesh and blood.
Luther's large Catechism