The one to whom Christ gave the gifts can be stated clearly. Alternate translation: "Christ gave these offices to the church" or "He gave people with these responsibilities to the church (See: [[rc://en/ta/man/jit/figs-explicit]])
Paul is speaking of people who grow spiritually as if they were doing exercises to increase the strength of their physical bodies. (See: [[rc://en/ta/man/jit/figs-metaphor]] and [[rc://en/ta/man/jit/figs-idiom]])