on the Necessity of Baptism

Hilary of Poitiers On the Trinity book 8 par 8 (300-367 ad)
These are not our own conjectures which we offer, nor do we falsely put together any of these things in order to deceive the ears of our bearers by perverting the meaning of words; but holding fast the form of sound teaching we know and preach the things which are true. For the Apostle shews that this unity of the faithful arises from the nature of the sacraments when be writes to the Galatians. Fear as many of you as were baptized into Christ did put on Christ. There is neither few nor Greek, there is neither bond nor free, there is neither male nor female; for ye are all one in Christ Jesus. That these are one amid so great diversities of race, condition, sex,--is it from an agreement of will or from the unity of the sacrament, since these have one baptism and have all put on one Christ? What, therefore, will a concord of minds avail here when they are one in that they have put on one Christ through the nature of one baptism?