Baptism
1 Peter 3:20-21
In the days of Noe, when the ark was a building... eight souls were saved by water. Whereunto baptism being of the like form, now saveth you also: not the putting away of the filth of the flesh, but the examination of a good conscience towards God.
Context of the passage
Peter draws a typological parallel between the Flood, which saved Noah's family through water, and the saving power of Christian baptism.
Catholic reading
Peter states explicitly that 'baptism now saveth you,' directly attributing genuine saving power to the sacrament itself, while clarifying its effect is spiritual (a cleansed conscience united to Christ's Resurrection), not mere external hygiene.
Common objection
This verse says baptism saves only as 'an appeal/answer of a good conscience,' meaning it's the believer's internal response of faith, not the physical water rite, that actually saves.
Response
Peter does not oppose the physical rite to its spiritual meaning but unites them: baptism is the very act 'now' declared to save, precisely because it engages a good conscience through faith while the water itself, by Christ's institution, is the effective instrument of that grace, not merely a coincidental accompaniment.