You need both.
You would need to bring your NJ MMP ID card and another form of government photo ID.
You need to get your temporary ID card, print out online, and bring it with you when you go. Everything the doctor gave you, there's paperwork you need to have in addition to your card. It's the paperwork they gave you to get your card. Bring both-- it's mandatory. That paper is as important as the card is.
I think both if it's your first visit.
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