I’m not sure I get the concept of a “retired missionary or minister” of the gospel. Since God has called us to work, the idea of retiring from the work He has engaged us in seems to go against the the divine mandate. Should we not work until ability fails us? Are we called to the ministry or are we just working a career? And if we look forward to the day of retiring from ministry, are we not being selfish? God has called us to work, not retire. The rest we receive will be that which we are given when this fleshly garb expires and we find ourselves in the rest in the fulfilled promise of our Father through His Son Jesus Christ. When we are no longer able to work the way we have always worked, then the nature of our work should change to whatever ability God has been gracious enough to equip us with. We are to redeem every moment until God retires us. To choose to do this for ourselves, we are saying that we are sovereign in our lives. We must redeem every moment, we are not our own!