In Chapter 9, one of the things Paul is sharing is his commitment to evangelism, sharing the gospel. He views his responsibility for the gospel as a sacred trust. In fact in 2 Timothy 2:2 he uses a financial term that describes trusts in describing what Timothy is to give to those whom he is equipping.
The great commission tells us that we are all, like Paul, entrusted with what Jesus taught the disciples. That is validated by Christ’s prayer in John 17:20. We share that trust that was given to Paul.
Paul was gifted. He was at least gifted in teaching, exhorting, and probably as an evangelist, My gifts include exhortation and leadership, but not evangelism. But that does not absolve me of the responsibility, the trust, the requirement to share the gospel.
Regardless if I do it voluntarily or as a stewardship, it is still my assignment.