Keeping Covenant

 

It's not evident in the Scripture that the apostolic approach to dealing with serious error or the threat of apostasy is always to question conversion.  The more typical New Testament approach is to exhort such persons to faith.  This is seen in the Epistle to the Hebrews, and in 1 Corinthians.  To the Galatians, Paul complains that he must give birth to Christ anew within them (even though they are church members).  It's the more typical case that the threat of heresy or apostasy is handled not by questioning hearers' conversions, but by exhorting them to faith and perseverance.  

 

This is more in keeping with the doctrine of the visible church, which is the Mother of believers, and the Household and Family of God, where "children" are born and raised spiritually (as well as literally).  The visible church is not the exclusive fellowship of persons who become converted outside and were allowed in afterward.