Paul continues to give instructions to believers on how to live and speak.
Here the word “us” refers to Paul and Timothy but not the Colossians. (See: rc://en/ta/man/translate/figs-exclusive)
“Keep praying faithfully” or “Keep praying consistently”
Opening a door for someone is a metaphor for giving that person the opportunity to do something. AT: “God would provide opportunities” (See: rc://en/ta/man/translate/figs-metaphor)
“Word” here is a metonym for “message.” AT: “make an opportunity for us tp preach his message” (See: rc://en/ta/man/translate/figs-metonymy)
This refers to the gospel of Jesus Christ, which was not understood before Christ came.
Here “chained” is a metonym for being in prison. AT: “It is for proclaiming the message of Jesus Christ that I am now in prison” (See: rc://en/ta/man/translate/figs-metonymy)
“Pray that I might be able to speak the message of Jesus Christ clearly”