Acts 1:8 (NASB)
You shall be my witnesses.
A witness doesn't speak of himself but about a person or act he has seen. God has called every blood-washed saint to be a royal priest and a witness to the risen Christ (Acts 5:32, 1 Peter 2:9). There is a misconception among believers that it is only a preacher's job to be a witness for Christ through preaching, teaching, and evangelism. On the contrary, a minister has only minimal influence and role in witnessing. A pastor may train and equip the saints to go out and share the gospel. But he may not go out to the workplace. But the workplace is where the sinners are. Hence, a minister has minimal outreach. It is the responsibility of the saint to share the gospel with their colleagues. This doesn't mean the saint harasses his friends to share the gospel. When the people of this world see the saint praying, studying, or meditating over the Bible, a witness unto Christ is presented. That will open doors for further discussion and sharing of Christ.
It is equally valid that some ministers think that lay people are not doing spiritual work but just making a living. That would be incorrect as well. For example, God designated Stephen the martyr to be a waiter while the Apostles devoted themselves to preaching (Acts 6:5). Does that mean that Stephen was not doing any ministry just because he was doing secular work, like waiting on tables? No. Stephen saw the glory of God (Acts 7:56) and probably had a much greater reward in heaven than Saul or the Apostle Paul, his killer.
God calls us all to different vocations. Not all saints are preachers, and not all ministers are professionals. But to each, God has given gifts to enable them to witness unto the Lord Jesus Christ right where they are (1 Corinthians 12: 7-17). And we will all be judged according to the responsibilities and gifts given to us, not someone else (Matthew 25:23).