持参 and 持ち込む: bringing a needed item and bringing it into a site
Compare bringing identification along with bringing drinks into a library. Read the needed-item purpose and the relation of bringing an outside item into the specified place.
Bring the needed item along
持参, read じさん, means bring or carry with one. 受付には身分証明書を持参してください。 asks someone to bring identification to reception.
Identification is the item to bring along. The request does not establish arrival at reception or completed submission.
Bring an outside item into the site
持ち込む, read もちこむ, means bring in or take to. 図書館には飲み物を持ち込まないでください。 asks people not to bring drinks into the library.
The site is the library and the object is drinks. A prohibition request is not an actual bringing-in event, and this example does not establish other facilities' rules.
Read the purpose and the completed assistance
昼食を持参したので、食堂で温めてもらった。 says that someone brought lunch and had it heated in the cafeteria. Bringing lunch and receiving the heating assistance are both stated.
修理のため壊れた時計を店へ持ち込んだ。 says that someone brought the broken clock to the shop for repair. Bringing it is completed; repair is the purpose rather than an established completed result.
What relationships matter when comparing a request to bring an item along (持参) with a request not to bring it into a site (持ち込む)?
Show the answer and why
Bringing a needed item along versus bringing an outside item into the specified site. Keep requests and prohibitions separate from completed actions.