Obligation to assume

An older editorial 2nd part by Challies in which he sets down criteria for assuming someone is actually a Christian.

When a person has made a profession of faith and is a member in good standing of a true church, as defined by these three marks: the preaching of the Gospel, the administration of the sacraments and the exercise of church discipline, I believe that we are under an obligation to assume that this person's faith is genuine. (emphasis mine)

This is a very traditional definition. The article is a good defense for the importance of discipline one considering the unity of the church.