6 So they began their circuit of the villages, preaching the Good News and healing the sick. (Luke 9:1-6 NLT)
After being with Jesus, it was time for the Disciples to put Jesus' teachings into practice. So He sent them out to "practice" doing the things they would be doing after His death and resurrection. We might call this an internship or on the job training. My most valuable training during my time in the seminary was at my field work congregation where I got to experience ministry and at my vicarage (internship) congregation where I got to practice ministry.
It is not enough for us to worship the Lord and listen to Him. We need to put His Words into practice. He sends us out to tell everyone about the Kingdom of God. The way we will get better at telling and helping others is by practice. Practice does not make us perfect, but it does make us better.