You can judge the quality of their faith from the way they behave. Discipline is an index to doctrine.
TertullianWhen we are going to enter the water ... in the presence of the congregation and under the hand of the president, we solemnly profess that we disown the devil, his pomp, and his angels. After this we are immersed three times, making a somewhat larger pledge than the Lord appointed in the Gospel. Then we are taken up [a reference to the Roman tradition of recognizing a newborn baby as a member of the family]. We first taste a mixture of milk and honey and from that day we refrain from the daily bath for a whole week.
TertullianIt is a fundamental human right, a privilege of nature, that every man should worship according to his own convictions.
TertullianIf we refuse our homage to statues and frigid images, the very counterpart of their dead originals, with which hawks, and mice, and spiders are so well acquainted, does it not merit praise instead of penalty [Christians were punished for not worshiping Roman gods] that we have rejected what we have come to see is error? We cannot surely be made out to injure those whom we are certain are nonentities. What does not exist is in its nonexistence secure from suffering.
Tertullian