Matthew 7:7–8 (King James Bible) ask and it shall be given you seek and ye shall find knock and it shall be opened unto you for every one that asketh receiveth and he that seeketh findeth and to him that knocketh it shall be opened
This biblical quotation is based on Matthew 7:7–8; overall it is paraphrastic in 3 Nephi 27:29, but in many instances the phraseology is exactly the same. The one case of interest here is that in the printer’s manuscript scribe 2 wrote “& to him that knocketh it shall be opened”, which follows exactly the King James phraseology in the last part of Matthew 7:8. However, Oliver Cowdery (when he proofed 𝓟 against 𝓞) corrected the preposition to to unto. The 1830 edition, set here from the original manuscript, has unto, so unto was undoubtedly the reading in 𝓞. Both Oliver and the 1830 typesetter probably wouldn’t have independently emended the text to unto since there is nothing wrong with to. The Book of Mormon text is in this regard more consistent than the King James Bible since in Matthew 7:7 we have unto in “knock and it shall be opened unto you” but in Matthew 7:8, the next verse, we have to in “and to him that knocketh it shall be opened”. Scribe 2’s to is probably just a simple scribal error on his part, especially since to is what we expect in modern English.
Summary: Maintain in 3 Nephi 27:29 the preposition unto in “and unto him that knocketh it shall be opened”; even though scribe 2 wrote “to you” (the King James reading) in the printer’s manuscript, the original manuscript undoubtedly read “unto you” since Oliver Cowdery corrected scribe 2’s to to unto and the 1830 edition independently has unto.