As noted here, Francis just said that: "..the Eucharist is not the reward of saints, but the bread of sinners."
While it is true that the Holy Mass is ordered to the forgiveness of venial sins, those conscious of grave sin should not approach the Eucharist.
Paragraph 1395 of the Catechism of the Catholic Church:
"By the same charity that it enkindles in us, the Eucharist preserves us from future mortal sins. The more we share the life of Christ and progress in his friendship, the more difficult it is to break away from him by mortal sin. The Eucharist is not ordered to the forgiveness of mortal sins - that is proper to the sacrament of Reconciliation. The Eucharist is properly the sacrament of those who are in full communion with the Church."
In 1 Corinthians 11: 27-29 we read [those of us who, unlike Francis, actually read Sacred Scripture]: "Therefore whoever eats the bread or 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."