God gives us our Mission in His Word; it’s not something we try to creatively come up with. And yet the Bible is a big book, so we make our attempt to summarize what He has called His church to do and be.
One way to narrow our focus and clear-up some confusion is to distinguish:
(1) the mission of a local church / from the mission of God, and
(2) the mission of Jesus while here on earth / from the mission, passions and responsibilities of individual Christians.
What has God in His Word called us to be and to do? The Church is “the pillar and ground of the truth” (1 Tim. 3:15) – that is what we are. We are to support, defend, publish and preach the Word of God. “My house shall be called a house of prayer” (Matt. 21:13). Prayer must be a priority. As the collective temple of God (2 Cor. 6:16, 1 Pet. 2:5) we are to facillitate God-honoring worship. We are also to equip believers “for the work of ministry” and build up the body of Christ to maturity in love (Eph. 4:11-16). As the body of Christ (Rom. 12:4-8; 1 Cor. 12:12-27), we are called to give ourselves to the service and the strengthening of one another. We are also called to be lampstands (Rev. 1:20) and to “make disciples of all nations” (Matt. 28:18-20). Edification and evangelism in the power of the Spirit according to the truth of Scripture are to be our constant petitions and missional priorities.
Our mission is to preach Christ, to love and worship our triune God, to love one another, to seek and love the lost, to strive to become more and more like Jesus Christ and to pray thankfully, that His Holy Spirit would empower and work in us to do all these things.