Willem Teellinck (1579-1629) was one of the earliest leaders of the Dutch Nadere Reformatie. He placed a heavy emphasis on the absolute necessity of personal conversion. Teellinck is a direct link between English Puritanism and Dutch Reformed thought. He was himself converted in England and was deeply moved by the Puritan emphasis on God as the centre of one’s whole life. His wife was also English, and a Puritan. His first work was a translation of a work of William Perkins into Dutch. Teellinck’s Housebook (Huysboek ofte Eenvoudige verclaringhe ende toeeygheninghe van de voornaemste Vraegh-stucken des Nederlandtschen Christelijcken Catechism) is a commentary on the Compendium of the Catechism, showing how he viewed the Heidelberg Catechism as a worthy centre of family worship.
Teellinck argues that one must see baptism not as a seal of our faith toward God, but of his grace toward us, which precedes any response we give. One learns of God’s grace to the children of believers when one understands the Scripture as a whole. In the New Testament, it is as if Christ is saying:
“I have formerly made my grace to the Jewish people clear and caused my grace to be sealed on them through circumcision, which was performed on the covenant members and their children. Go now and teach all the nations that my grace also stands open for them as much as the Jewish people, and seal those who gladly receive your words and their children tough baptism.”
– Willem Teellinck (1579-1629), Huysboek ofte Eenvoudige verclaringhe ende toeeygheninghe van de voornaemste Vraegh-stucken des Nederlandtschen Christelijcken Catechism, p. 485-486
The believing parents must bring their children to Christ, for “the children still should be externally brought to the fellowship of the things of Christ” (p. 489) through baptism. The parents pledge their children to God in light of God’s giving this seal promising “as soon as they come to any degree of understanding to educate them in the Christian doctrine to which they were given over through baptism… so that they even at an early age can give a sweet and lovely confession of faith.” (p. 491-492)
Teellinck makes it clear that he does not mean by covenantal holiness that the infants of believers are in a state of redemption when he discusses 1 Cor. 7:14, which says that children of at least one believing parent are not unclean but holy:
“This cannot be understood to refer to the general impurity and depravity of nature, for all children are polluted with that, even the children of believers… So this refers to nothing other than that the children are not unclean, but holy… with respect to the covenant of grace… So that here these children are testified to be holy as the entire people of Israel were said to be holy, that is, set apart from other peoples and in a state to be permitted to use externally the holy things of God… even though there were many of them that are at the same time found to be unholy in themselves (Lev. 20:26).” (p. 501-502)
Here one sees a clear exposition of external holiness, emphasizing the continuity with the Old Testament in covenantal holiness. Many of the Old Testament Israelites were not internally holy, and the same applies to the children of believers. In this line, in another work of Teellinck titled Hemelsche Openinge van de Zeghelen des Verbonds der Ghenade, p. 22, he calls baptism “an external sign of conversion.”