As a poem, I like it. But, “Salvation, then, is worked by men,” is too strong a statement. The partnered idea, “God gives the call to obey,” is definitely true and a valid theme as you present it. But stating flat out that salvation is worked by men will cause the point to be rejected by most of the religious world before it is even fully stated. And the sentiment that we must accept that there are things God expects us to do does need to be heard.