According to the Catholic Church, what did Jesus mean by saying “Least of these commandments "?

We see Jesus saying at Matthew 5:18-19 : > For truly I tell you, until heaven and earth pass away, not one letter, not one stroke of a letter, will pass from the law until all is accomplished. Therefore, whoever breaks one of the least of these commandments, and teaches others to do the same, will be called least in the kingdom of heaven; but whoever does them and teaches them will be called great in the kingdom of heaven. I am interested in knowing as to what Jesus meant by `these commandments'. Did he refer to the Ten Commandments and if so, which ones are the least of the commandments, according to the Catholic Church ?