There has never been a more deceptive false teacher in the history of professed Christianity than Tertullian:

http://www.earlychristianwritings.com/tertullian.html

Tertullian's doctrine of magic water that saves as a substitute for the true gospel should be obvious to all.

Yet ALL PROTESTANT SECTS IN EXISTENCE (including 'trail of blood' Baptists) continue to promote the absolute lie that Tertullian was a true gospel believer. This lie was promoted by men such as John Gill and, of course, is believed and taught by all Protestant scholars. They know what they are doing.

Benjamin B. Warfield in his book 'Tertullian and Augustine' defends the orthodoxy of Tertullian strictly on the basis that T. formed a more clear and precise doctrine of the Trinity than had existed previously. The implication is that no stalwart defender of the Trinity could be an enemy of the gospel. THE LIE OF THE AGES. Unregenerate men steeped in pagan philosophy and superstition can define many aspects of the truth; they just can never grasp the comprehensive truth of the gospel in all of its aspects.

I encourage all to read various writings from the link above and comment on whether Tertullian knew anything of the gospel.