Question about mortal sin and the state of grace?
Therefore whosoever shall eat this bread, or drink the chalice of the Lord unworthily, shall be guilty of the body and of the blood of the Lord. - 1 Corinthians 11:27
To receive Communion in the state of mortal sin is a far worse sin a sacrilege. To receive Communion in a unworthy manner adds the gravity of the soul’s sinfulness, for one has consumed the body and blood of Our Lord Jesus Christ, soul and divinity in the state of serious sin.
To receive any sacrament of the church (except baptism and penance) in mortal sin is to commit a sacrilege, which, as the Baltimore Catechism points out, is “a great sin, because it is an abuse of a sacred thing.” However, receiving the Eucharist in an unworthily manner also brings about judgment, as explained in the Bible as well as contemplated by some of the great saints and fathers of the church.
“Whoever eats the bread and drinks the cup of the Lord unworthily will have to answer for the body and blood of the Lord. A person should examine himself, and so eat the bread and drink the cup. For anyone who eats and drinks without discerning the body, eats and drinks judgment on himself. That is why many among you are ill and infirm, and a considerable number are dying.” (I Cor. 11:27-30)
Saint Paul did not pull any punches when he warned of the dangers of receiving the Eucharist when you are in a state of grave sin. Saint Paul did not treat the reception of the Eucharist as a “right” or an “obligation because everyone else is doing it”. He did not treat the Eucharist as bread and wine. He did not treat the Eucharist as a “routine” and “something I have do to.” He treated it as Jesus. He treated it as the Real Presence of the Son of God and warned against mistreating it. When you receive the Eucharist in an unworthy manner you are mistreating the body and blood of Jesus Christ. Just because one does not believe in the transubstantiation does not make it untrue. One’s unbelief does not make the truth a lie. It only brings forth judgment and danger upon the unbeliever.
Canon Law 916 addresses this by stating that a person “conscious of grave sin” should not “receive the body of the Lord without previous sacramental confession.” The Canon Law places an obligation on each individual to seriously take an examination of your conscious and your soul before receiving the Eucharist. Just because you are at Mass does not mean you must receive the Eucharist and just because you have always received it each week does not mean you have to receive it if you are in a state of grave sin.
As Catholics, we must get away from just going through the motions and making Jesus a routine. If the Eucharist is sacred enough for us to genuflect before a tabernacle, pray and kneel in its presence during Adoration and profess it as the source and summit of the Christian life then we must know and confess it is more than a routine. It is more than a right. It is more than an entitlement. It is Jesus Christ and it is the body, blood, soul and divinity of the Son of God, of God Incarnate, which we receive. - The Grave Danger of Receiving the Eucharist Unworthily
To receive Communion in an unworthy manner is a more serious sin in the eyes of the Catholic Church.