XXI. Baptism (with respect to true believers) seals saving grace because it is connected with the internal baptism of the Spirit. But with respect to hypocrites, it does not have the accompanying grace of the Spirit, but is only a badge of profession by which they are distinguished from Jews, Turks and other unbelievers. And then it is administered, not from the force of election, but by reason of the general dispensation by which God determined by the word of the gospel and the administration of the sacraments to gather to himself a church, and by certain signs and marks to distinguish it from other and profane assemblies. Thus the doctrine of perseverance is not at all endangered here, which remains constant with respect to the elect.
Francis Turretin, Institutes of Elenctic Theology, ed. James T. Dennison Jr., trans. George Musgrave Giger, vol. 3 (Phillipsburg, NJ: P&R Publishing, 1992–97), 19.20.21 (p. 420).