Those with a Southern Baptist or Calvinist background often argue that baptism can’t be essential for salvation or else it would be a “work,” and Paul is very clear that it’s error – even damning error – to add a work to faith as a requirement for salvation. For example, in Gal 5, Paul writes,
(Gal 5:2-4 ESV) Look: I, Paul, say to you that if you accept circumcision, Christ will be of no advantage to you. 3 I testify again to every man who accepts circumcision that he is obligated to keep the whole law. 4 You are severed from Christ, you who would be justified by the law; you have fallen away from grace.
In other words, Paul argues that if you insist on any element of the law as a condition of salvation, you must apply the entirety of the law. We can’t pick and choose. And, obviously enough, no one can perfectly keep the entirety of the Law of Moses, and so adding any element of the Law of Moses creates a standard that cannot be met and which therefore damns.
Notice a couple of things. First, “law” is a reference to the Law of Moses. And, obviously enough, baptism is not part of the Law of Moses.
Second, baptism is a gift received, not a work done. It’s always spoken of in the passive voice in the NT. It’s never pictured as something that earns salvation.
However, both these arguments ultimately fail. Let’s start with the second point. Circumcision is even more of a gift received than a work done. Under the Law of Moses, infants are circumcised eight days after birth. Not only is it passive, the infant has no choice in the matter! And yet Paul plainly considers circumcision a “work” that leads to falling from grace.
As to the fact that baptism is not part of the Law of Moses, we need to keep reading in Gal 5 –
(Gal 5:5-6 ESV) For through the Spirit, by faith, we ourselves eagerly wait for the hope of righteousness. 6 For in Christ Jesus neither circumcision nor uncircumcision counts for anything, but only faith working through love.
The reason adding works to faith damns is not that works are particularly awful. It’s that they are not faith. Paul declares that only “faith working through love” or “faith expressing itself through love” (NIV) “counts for anything.” That is, only faith has the ability to accomplish what’s being discussed: justification.
The danger is not in adding works but in considering faith insufficient. In v. 4, Paul declares that our hope comes “by faith.” The problem with circumcision is not that it’s a “work” but that it’s not faith. Adding circumcision to faith as a condition of salvation makes faith insufficient – contrary to God’s covenant with Abraham and countlessly repeated promises over the centuries to save all with faith.
(Gal 2:16 NET) yet we know that no one is justified by the works of the law but by the faithfulness of Jesus Christ. And we have come to believe in Christ Jesus, so that we may be justified by the faithfulness of Christ and not by the works of the law, because by the works of the law no one will be justified.
(Gal 3:2 ESV) Let me ask you only this: Did you receive the Spirit by works of the law or by hearing with faith?
(Gal 3:5-9 ESV) Does he who supplies the Spirit to you and works miracles among you do so by works of the law, or by hearing with faith – 6 just as Abraham “believed God, and it was counted to him as righteousness”? 7 Know then that it is those of faith who are the sons of Abraham. 8 And the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, “In you shall all the nations be blessed.” 9 So then, those who are of faith are blessed along with Abraham, the man of faith.
(Gal 3:11-14 ESV) Now it is evident that no one is justified before God by the law, for “The righteous shall live by faith.” 12 But the law is not of faith, rather “The one who does them shall live by them.” 13 Christ redeemed us from the curse of the law by becoming a curse for us – for it is written, “Cursed is everyone who is hanged on a tree” – 14 so that in Christ Jesus the blessing of Abraham might come to the Gentiles, so that we might receive the promised Spirit through faith.
(Gal 3:22-26 ESV) But the Scripture imprisoned everything under sin, so that the promise by faith in Jesus Christ might be given to those who believe. 23 Now before faith came, we were held captive under the law, imprisoned until the coming faith would be revealed. 24 So then, the law was our guardian until Christ came, in order that we might be justified by faith. 25 But now that faith has come, we are no longer under a guardian, 26 for in Christ Jesus you are all sons of God, through faith.
In chapters 2 and 3, Paul builds his case on the sufficiency of faith in Jesus to save. His point in chapter 5 is that only faith saves – and so adding anything to faith as a condition of salvation ultimately establishes a burden greater than anyone can bear – because whatever logic leads to adding the something extra will require you to pile on more and more until few people, if any, can be saved.
This is exactly the experience of the 20th Century Churches of Christ. Early on, even before the Civil War, many argued that baptism strictly in accordance with Church of Christ teaching was essential for salvation.
Soon other requirements were added. To faith in Jesus must be added not only an impeccable baptism but also a cappella worship, objection to missionary societies, rejection of located preachers, rejection of fund raising by any means other than a free will offering, no use of the church treasury for unauthorized purposes, no having only one elder, no having elders with only one child or a deceased child, etc., etc., etc. And the number of saved people declined with each issue of each editor-bishop’s periodical.
Paul saw the danger with the eyes of prophecy. He wrote,
(Gal 5:13-15 ESV) For you were called to freedom, brothers. Only do not use your freedom as an opportunity for the flesh, but through love serve one another. 14 For the whole law is fulfilled in one word: “You shall love your neighbor as yourself.” 15 But if you bite and devour one another, watch out that you are not consumed by one another.
When we add to faith as a requirement of salvation, we soon find ourselves biting and consuming each other. Love is the first casualty of a “gospel” that finds faith in Jesus insufficient to save.
In short, there’s no error in saying that baptism is the moment when God saves in the ordinary case. I think that’s exactly the case. But if we insist that those improperly baptized are damned, then haven’t we treated baptism just like circumcision? How would we not be guilty of the Galatian heresy?
 Some have objected to this line of reasoning on the basis that there is no “only” in the Greek. However, alla may be translated “only” or “but” or, as in the ESV, “but only.” See, for example, Richard N. Longenecker, Galatians (Word Bible Commentary 41; Accordance electronic ed. Grand Rapids: Zondervan, 1990), 229, translating alla as “only” in 5:6.
Paul has already declared that faith, through the Spirit, provides our hope of salvation (v. 5). And so it’s hard to translate v. 6 without an “only” because Paul’s point is that faith, expressing itself through love, is what “counts” or “avails” (KJV) in contrast to any other possibility. If something has to be added to faith for it to count, then faith doesn’t avail (that is, suffice or accomplish its intended result).
Hence, many translations use “only” or “but only,” including the ESV, NAB, NET, NIB, NIRV, NIV, NJB, NRS, and TNIV. The translation hardly reflects a Calvinist or Baptist bias when the Catholic New Jerusalem Bible adds the “only”!
The Louw-Nida Greek lexicon notes that alla is —
a marker of more emphatic contrast (as compared with de 89.124) – ‘but, instead, on the contrary.’
Bryan Findlayson notes in the technical notes to his “Lectionary Bible Studies” that the alla is adversative, that is, meaning “but only,” citing the highly respected Theological Dictionary of the New Testament.
The combination oute/alla is parallel to Galatians 1:12 —
(Gal 1:12 ESV) For I did not receive it from any man, nor was I taught it, but I received it through a revelation of Jesus Christ.
Paul’s point in 1:12, of course, is that the gospel he received came only from revelation and not some blend of human and divine sources.
This meaning is clear from the context as well. Suppose Paul meant —
(Gal 5:6 ESV) For in Christ Jesus neither circumcision nor uncircumcision counts for anything, but … faith working through love [as well as some other unspecified things].
If that’s a proper translation, how does Paul’s logic flow? It doesn’t. If Paul admits that justification may be found in something other than faith working through love, then circumcision might be one of the other things essential for justification. He’s not made his point unless he is saying that circumcision and uncircumcision both fail to be essential for salvation because neither is faith working through love.
 The KJV “avails” and ESV “counts for anything” translate the Greek ischuō, meaning “to be able to, to have the strength to, to be very capable of,” Louw-Nida.