## Continue steadfastly in prayer​  ##

"Keep praying faithfully" or "Keep praying consistently."

## for us also ##

The word "us" refers to Paul and Timothy but not the Colossian believers.

## God would open a door  ##

This is an idiom for "God to provide opportunities." (See: [[rc://en/ta/man/translate/figs-idiom]])

## mystery of Christ ##

The message of Jesus Christ that was not understood before Christ came.

## Because of that word, I am bound​  ##

"It is for proclaiming the message of Jesus Christ that I am now in prison"

## pray that I may make it clear and that I may speak as I ought to speak​  ##

"pray that I might be able to speak the message of Jesus Christ clearly as I should speak."