Why Do We Only Baptize Once (But Observe the Supper Repeatedly)?

Thomas Goodwin on Regeneration and Baptism from Works, 6:408

And (2.) this great change is made but once. There is but ‘one baptism,’ as ‘one faith;’ and as the faith was but once delivered to the saints, Jude 3, so baptism is but once to be administered. And why? Because the thing signified, sealed up thereby, which is regeneration, is but once wrought (but the Lord’s supper is often celebrated, 1 Cor. xi.,’ As oft as ye receive’), which is therefore called a ‘baptizing into the likeness of his death and resurrection,’ Eph. vi. 4, 5. And that in two respects, which are the same with those before. 1. Inasmuch as Christ died but once, and rose but once, Heb. vii. 27, and Heb. ix. 26, 27, ‘Once in the end of the world he died, and offered up himself, even as it is appointed for men once to die.’ And 2. That the estate he rose into is an eternal state of life: Heb. x. 12,’ He forever sat down on the right hand of God.’ Now both these the apostle applies in that Rom. vi., unto men regenerated, and baptized into Christ, by instituting the parallel between our state by regeneration, signified by baptism into Christ’s death and resurrection, and Christ’s death and resurrection itself, in both these very respects fore-mentioned, in these words, ver. 9, 10, 11, ‘Knowing that Christ being raised from the dead, dieth no more; death hath no more dominion over him. For in that he died, he died unto sin once, but in that he liveth, he liveth unto God. Likewise reckon ye also yourselves to be dead indeed unto sin, but alive unto God through Jesus Christ our Lord.’ From whence he infers, ver. 12, that ‘sin shall not reign.’ It is a promise, as well as a command. And those words, ‘Likewise reckon yourselves,’ import the parallel to lie in this, that as Christ died but once, and rose but once, so we are planted by baptism and regeneration (which work bears the resemblance of his death and resurrection, and whereof baptism is the sign) but only once. And thus as, in Heb. ix., we heard the apostle saying, that Christ died ‘ but once,’ so in Heb. x. 26 we read, that for that very reason it is, that ‘those that have been illuminated, and made partakers of the Holy Ghost,’ &c. (of whom you read in the 6th chapter of that epistle), that if they shall ‘sin wilfully, after they have received the knowledge of the truth, there remaineth no more sacrifice for sin:’ which is all one as to have said on Christ’s part for us, ‘for Christ died but once.’ And it is once, therefore answerably hereunto, there cannot be a new repetition of the work of regeneration, which they professed to have received at their baptism; which that 6th chapter of the Hebrews, verse 6, had given a clearer explanation of; that ‘those who have been enlightened, and tasted of the good word of God, and have been partakers of the heavenly gift, &c., if they shall fall away, it is impossible to renew them again unto repentance.’ And why ? But because as Christ died but once, so men are renewed but once. And therefore those that hold total falling away from regeneration, must either hold no second regeneration for such, which is to put them into despair; or they must say, that regeneration is often reiterated, and then that baptism, the sign of it, ought also to be repeated (even as the Lord’s supper is), and then Christ’s death reiterated also; for these are parallels in the apostle’s intention.