The word "us" refers to Paul and his co-workers but not the Colossian Believers.
## may encourage your hearts ##
"your hearts" is an expression for the person. "may encourage you" (See: [[rc://en/ta/man/translate/figs-synecdoche]])
## Onesimus ##
Onesimus was a slave of Philemon in Colossae. He stole money from Philemon and ran away to Rome where he became a Christian through the ministry of Paul. Now Tychicus and Onesimus are the ones bringing Paul's letter to Colossae.
## faithful and beloved brother ##
Paul considers Onesimus a fellow christian and servant of Christ.
## They will make known ##
"Tychicus and Onesimus will make known"
## that are done here ##
They will tell the Colossian believers all that is taking place where Paul is currently residing. Tradition has Paul in Rome under house arrest or in prison.