NET
21 Since I was confident that you would obey, I wrote to you, because I knew that you would do even more than what I am asking you to do.
Darby
21 Being confident of thine obedience, I have written to thee, knowing that thou wilt do even more than I say.
KJV
21 Having confidence in thy obedience I wrote unto thee, knowing that thou wilt also do more than I say.