A Holy Household (Ephesians 6:1-4)

The Apostle Paul exhorts children to obey their parents for this is pleasing to the Lord.  It is not a surprise to us that Paul would exhort children to obey their parents, but what does this imply about their status in the church?  Why is the context of their exhortation so significant? Why is it important that this exhortation seems to echo the Old Testament?  What could this imply about children being in covenant with the Lord?