Don't sing another man's song is about impact About the impact a visionary leader has on those who work with him Don't Sing Another Man's Song is about vision and leadership. Wachira Ngamau is a man of vision; he invests twenty years into a child so that child will become a Christian leader to his tribe or country. He is a man of leadership; moving pastors from all denominations to see "beyond the pulpit" to the community, the region and the continent as their mission field.