This verse is similar to Colossians 4.3d-4.

For the sake of this gospel translates the phrase “on behalf of which”; the antecedent of the relative pronoun may be “the gospel” or “the secret” (so Abbott), or the phrase can mean simply “For this reason” (so Barth).

In most languages it is relatively easy to speak of someone who has benefited by an event, but it is not always easy to use a simple phrase to explain a benefit which might accrue to the gospel. Some persons have attempted to use the phrase “in order to help the gospel,” but this may seem both strange and obscure. Perhaps the most satisfactory equivalent in some languages is simply “in order to tell others about the gospel” or “in order that more people may know about the gospel.”

I am an ambassador translates a Greek verb used only here In some cases it may be necessary to specify the person or institution that one represents as an ambassador. Therefore the clause I am an ambassador may require amplification, for example, “I am an ambassador of Jesus Christ” or “I am a spokesman for Jesus Christ.”

In prison: the writer refers to himself as a prisoner in 3.1; 4.1.

Pray: in a number of languages there is no specific term for pray, and therefore it may always be necessary to use a phrase such as “speak to God” or “ask God” or even “urge God.”

I may be bold in speaking translates a Greek verb which is related to the noun “boldness” in verse 19; this verb, “be a bold speaker,” is often used of Paul in the narrative in Acts (see 9.27, 28; 13.46; 14.3; 19.8; 26.26).

Quoted with permission from Bratcher, Robert C. and Nida, Eugene A. A Handbook on Paul’s Letter to the Ephesians. (UBS Handbook Series). New York: UBS, 1982. For this and other handbooks for translators see here .