Tertullian’s treatise, or sermon perhaps, on Baptism is the earliest work dedicated to the subject. It is interesting in many ways, but perhaps one of those more hotly debated refers to his apparent notion of the deferment of Baptism in chapter 18.
In traditional Baptist polemics, this is typically taken as an expression of surprise at attempts by others to innovate the Baptism of young ones. The reading is that Tertullian was quite unaware of the Baptism of young ones and was forcefully resisting it.
I find this interpretation somewhat difficult. The work is a rhetorical piece in large measure, and thus his aim is not only to transfer doctrinal content but to do so in a way that moves people to behave in a certain way, and this is much better done not by gavel-dropping but by persuasion, specifically appeal to self-interest in deferment: “cunctatio baptismi utilior est”. However, should Tertullian truly have considered the Baptism of little ones to have been a complete deviation from Apostolic tradition similar to the common Baptist claim, it seems incredible that he would have rested content with mere gentle persuasion on this point. He does not say, for instance, that it is better to believe in the Trinity or the resurrection of the flesh in his apologetic works: he is required to say that if you deny these things you are outside of the fold. Thus, whatever Tertullian is contradicting, he does not consider it not-baptism.
There is a second difficulty with his position, however, in that it seems unlikely, had Tertullian indeed believed the baptism of little ones to have been apostolic, that he would have counselled so strongly against it. How these two considerations are to be reconciled is for another place.
Little Ones
A second Baptist contention is that Tertullian wasnt actually referencing infant baptism, just young child baptism. Bunsen was pædobaptist as far as I can tell:
Tertullian’s opposition is to the baptism of young, growing children; he does not say one word about new-born infants. Neither does Origen, when his expressions are accurately weighed.
The word Tertullian uses is parvulus:
Itaque pro cuiusque personæ condicione ac dispositione, etiam ætate, cunctatio baptismi utilior est, præcipue tamen circa parvulos. […] Ait quidem Dominos, Nolite illos prohibere ad me venire: veniant ergo, dum adolescunt, dum discunt, dum quo veniant docentur: fiant Christiani cum Christum nosse potuerint.
This word does not only reference infants but, more often, young children. I think the calque “little one” is pretty accurate as it encompasses both of these referents. The age range would be below six or seven years old, not dissimilar to the Greek παιδίον which properly refers to a little one under (conscious!) instruction. Parvulus can, though, be used to refer to new-borns (see below).
This is made in direct reference to that saying of our Lord:
Sinite parvulos, et nolite eos prohibere ad me venire.
Ἄφετε τὰ παιδία καὶ μὴ κωλύετε αὐτὰ ἐλθεῖν πρός με.
It is true that St. Luke introduces the little ones in this scene as “infantes” and even makes something of it (καὶ τὰ βρέφη), however it is clear that Tertullian is referencing the Matthæan account:
Tertullian: […] nolite illos prohibere ad me venire
Luke: sinite pueros venire ad me et nolite eos vetare talium est enim regnum Dei
Matthew: sinite parvulos et nolite eos prohibere ad me venire talium est enim regnum cælorum
Other vulgar uses of parvulus to discern a taste for its usages:
Matt. 2: Et mittens eos in Bethlehem dixit ite et interrogate diligenter de puero parvulo et cum inveneritis renuntiate mihi ut et ego veniens adorem eum.
Isa. 9: Parvulus enim natus est nobis, et filius datus est nobis, et factus est principatus super humerum ejus.
Mark 10: Amen dico vobis: Quisquis non receperit regnum Dei velut parvulus, non intrabit in illud. [The emphasis is on being teachable and humble, not unconscious.]
1 Cor. 13: Cum essem parvulus, loquebar ut parvulus, sapiebam ut parvulus, cogitabam ut parvulus. Quando autem factus sum vir, evacuavi quæ erant parvuli.
Gal. 4: Dico autem: quanto tempore hæres parvulus est, nihil differt a servo, cum sit dominus omnium, sed sub tutoribus et actoribus est
Heb. 5: Omnis enim, qui lactis est particeps, expers est sermonis justitiæ: parvulus enim est.
When parvulus refers only to an infant, it is often obvious—natus est nobis—or the word is being used imagistically such as in Hebrews. They may exist, but I’ve never seen babies loquentes, for instance: they typically babble and splutter, not speak, so that reference is to talking, and thus reasonable, young children.
The notion that Tertullian may be referring to young children down to, say, two or three years, is not without other parallels in important Fathers such as St. Gregory Nazianzen a couple of centuries later:
But in respect of others I give my advice to wait till the end of the third year, or a little more or less, when they may be able to listen and to answer something about the Sacrament; that, even though they do not perfectly understand it, yet at any rate they may know the outlines; and then to sanctify them in soul and body with the great sacrament of our consecration.
Περὶ δὲ τῶν ἄλλων δίδωμι γνώμην, τὴν τριετίαν ἀναμείναντας, ἢ μικρὸν ἐντὸς τούτου, ἢ ὑπὲρ τοῦτο (ἡνίκα καὶ ἀκοῦσαί τι μυστικὸν, καὶ ἀποκρίνεσθαι δυνατὸν, εἰ καὶ μὴ συνιέντα τελέως, ἀλλ’ οὖν τυπούμενα), οὕτως ἁγιάζειν καὶ ψυχὰς καὶ σώματα τῷ μεγάλῳ μυστηρίῳ τῆς τελειώσεως.
Specifically, St. Gregory’s concern is that consciousness is better, even if not necessary, to the reception of Baptism. Of course, in the case of impending death, concerns over consciousness and future-focussed utility should not factor in: Κρεῖσσον γὰρ ἀναισθήτως ἁγιασθῆναι, ἢ ἀπελθεῖν ἀσφράγιστα καὶ ἀτέλεστα.
If emergency baptism pulled the age of Baptism lower over time as it developed, these data points seem to fit the trend.