Good News Translation your Christian duty represents the prepositional phrase en kuriō which appears in Greek at the end of the verse. The whole Greek phrase “is pleasing in the Lord” is unusual and does not seem to be exactly equal to the normal dative phrase “pleasing to the Lord” (Eph 5.10). The word “pleasing” is here in Greek (euareston) probably to be taken absolutely, that is, “pleasing to God,” and the prepositional phrase en kuriō may be taken in the same way as it is taken in verse 18 (see Lightfoot, Moule). So Good News Translation represents en kuriō by your Christian duty and euareston by what pleases God. New English Bible has “that is pleasing to God and is the Christian way,” Translator’s New Testament “this is pleasing to God and is what Christians should do”; see also Barclay Bible en français courant.

Your Christian duty must sometimes be rephrased as “as Christians you should” or “since you are Christians, you must.”

In a number of languages, there are quite distinct words for children depending upon the age. The most frequent distinctions involve (1) babies before they are weaned, (2) small children before they can talk satisfactorily, (3) children from the age of speaking until puberty, and (4) adolescents from the age of puberty until marriage. Probably the most satisfactory term is one which would designate children between the age of speaking until the age of puberty, though if at all possible, a more general expression should be employed.

Though in the Greek text the term parents refers specifically to father and mother, it seems rather anomalous in some languages to speak of “obeying your father and mother,” when in reality children are normally expected to obey the mother and the maternal uncle, that is to say, the brother of the mother. It is not advisable to try to introduce a cultural adaptation by introducing “mother and mother’s brother,” but it may be useful to employ a term for parents which designates a somewhat wider class of adults in the extended family.

Quoted with permission from Bratcher, Robert G. and Nida, Eugene A. A Handbook on Paul’s Letter to the Colossians. (UBS Handbook Series). New York: UBS, 1977. For this and other handbooks for translators see here .