This Sunday is Mission Sunday, a time to focus on the work of the foreign missions in the Church. You're a foreign missionary for Christ, whether you know it or not.
You know many people -- perhaps family members, friends or acquaintances -- who really don't know Christ. They might be baptized Christian, but the person of Christ is foreign to them. They're foreigners to the Kingdom of Christ and don't even know it. They may associate with believing Catholics, but they don't know Christ. If they knew Christ, they would become missionaries for Him.