Develop a hunger in the hearts of your adult students to have a passion and burden for missions. Pray for the persecuted church regularly, and share occasional updates about the victories or obstacles facing those who are suffering for the cause of Christ. Educate the members regarding the challenges that missionaries have in trying to evangelize unreached people groups. Pray specifically for our missionaries, and communicate with them through cards/letters or social media. Consider sending a care package to various missionaries from time to time. The class might be interested in committing to fill one or more Christmas packages for needy children. Make a concerted effort to give toward the annual World Missions offering at church. Perhaps the Sunday school class could take up a collection in addition to the gifts that individuals plan to donate on their own.