With Onesimus, a faithful and beloved brother, who is one of you. They shall make known unto you all things which are done here.
Onesimus - the slave mentioned in Philemon 1:10, Philemon 1:16, "a brother beloved:" Paul's son in the faith; therefore sent with Tychicus as his safeguard, and put under the spiritual protection of the whole Colossian Church, as well as of Philemon his master.
A faithful and beloved brother - `the faithful brother,' he being known to the Colossians as slave of Philemon, their fellow-townsman and fellow-Christian.
One of you - belonging to your city.
They shall make known unto you all (the) things. This repetition of "all my state shall Tychicus declare unto you," favours the reading in Colossians 4:8, "that he might (may) know your estate." It is unlikely the same thing should be stated thrice.