Recently, Nanci Pelosi was barred from receiving Eucharist by the Catholic Church, due to her public stance on abortion which contradicts the Catholic faith, considered a mortal sin by the Church. What is the biblical basis for denying someone in mortal sin the Eucharist?
What is the biblical basis for denying the Lord's Supper to those in mortal sin?
St. Paul speaks of this quite clearly!
26 For as often as you shall eat this bread, and drink the chalice, you shall shew the death of the Lord, until he come.
27 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.
28 But let a man prove himself: and so let him eat of that bread, and drink of the chalice. - 1 Corinthians 11:26-28
This has always been the teachings of the Church.
The Catholic Church sets out specific guidelines regarding how we should prepare ourselves to receive the Lord’s body and blood in Communion. First, you must be in a state of grace. “Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of profaning the body and blood of the Lord. Let a man examine himself, and so eat of the bread and drink of the cup” (1 Cor. 11:27–28). This is an absolute requirement that can never be dispensed. To receive the Eucharist without sanctifying grace in your soul profanes the Eucharist in the most grievous manner.
A mortal sin is any sin whose matter is grave and which has been committed willfully and with knowledge of its seriousness. Grave matter includes, but is not limited to, murder, receiving or participating in an abortion, homosexual acts, having sexual intercourse outside of marriage or in an invalid marriage, and deliberately engaging in impure thoughts (Matt. 5:28–29). Scripture contains lists of mortal sins (for example, 1 Cor. 6:9–10 and Gal. 5:19–21). For further information on what constitutes a mortal sin, see the Catechism of the Catholic Church.
The Church’s ancient teaching on this particular matter is expressed in the Didache, an early Christian document written around A.D. 70, which states: “Whosoever is holy [i.e., in a state of sanctifying grace], let him approach. Whosoever is not, let him repent” (Didache 10).
Those publicly supporting abortion are guilty of creating a grave scandal in the eyes of many Catholics.