It's a judgment call with the penitent and the confessor, so you'll hear many interpretations of serious sin from priests and people alike. In previous centuries serious sin governed so many cases that few people received communion regularly, but that is not the case today. These offenses form a basis for figuring out which sins require confession before communion. Although confession is not required before every communion, it often precedes in church practice. Most parishes offer confessions on Saturday before communion on Sunday.
Children preparing for first communion also prepare for first confession.
Although the church does not oblige us to confess lesser sins, those who use the sacrament will find their communion more fruitful. Paul Turner, pastor of St. John Regis Parish in Kansas City, MO., holds a doctorate in sacramental theology from Saint Anselmo University in Rome. The priest consecrates the bread and wine. We call upon the Holy Spirit to make the bread and wine become, in fact, the body and blood of Christ. Holy, holy, holy Lord, God of power and might.