Gustaf Wingren (1910-2000) was no ivory tower theologian. He spoke out about the necessary consequences of the gospel for the church.
A recent review article on Wingren shines light on many of his achievements but neglects his strong defense of Lutheran ministry over against those traditions which require a sacramental, hierarchical episcopate (Lutheran Quarterly 23:2, 198-217).
Wingren knew that required structures are an attack on Christ himself because they undermine salvation by faith alone in Christ alone by the cross alone.
Read Wingren on ministry and church here and here. Both essays are found under “Major Theological Issues/Church and Ministry” on this website.