I can appreciate your argument concerning Tertulians belief in an cleansing nature to Baptism but what do you make of the rest of Tertullian's saying?Doubting Thomas said:Check out the last sentance again:
"If anyone understands the weighty imporatance of baptism, he will fear its reception more than its delay. Sound faith is secure of salvation."
Tertullian was a strict rigorist who like many believed that it was very hard to have sins forgiven after baptism. He, like some others, therefore recommended delaying baptism because of this "weighty importance"..in washing away sins. (In some more extreme cases--Constantine, for instance--baptism was delayed until at the end of life) He wanted children to thus be able to reach the age of "sound faith" and reason (ie "able to know Christ") before receiving baptism. This rigorist position was not the majority position but was more characteristic of schismatic groups like Novatians and Montanists (the latter which Tertullian eventually joined)
And so, according to the circumstances, disposition, and even the age of each individual, the delay of baptism is perferable. This is particularly true in the case of little children. For why is it necessary - if baptism itself is not so necessary - that the sponsors likewise should be thrust into danger?.... Let the children come, then while they are growing up. Let them come while they are learning- while they are learning where to come. Let them become Christians when they have become able to know Christ. Why does the innocent period of life hasten to the remission of sins?...
This appears to cast some doubt, one might draw from say Cyprian and Augustine concerning a 'necessity' that Children be cleansed through Baptism as Tertullian appears to know nothing of this practice? Let them become Christians when they have become able to know Christ... A case can be made that this is a fine argument for Believer's Baptism at a rather early date.
Have you given this any consideration before?
Be Well.