The Messenger of Allah ﷺ said to Muaz bin Jabal when he sent him to Yemen, "You are going to a people who are People of the Book. When you come to them, call them to testify that there is no god but Allah and that Muhammad is the Messenger of Allah. If they obey you in that, then inform them that Allah has made five prayers obligatory upon them every day and night. If they obey you in that, then inform them that Allah has made charity obligatory upon them, taken from their wealthy and given back to their poor. If they obey you in that, then beware of taking the most prized of their wealth, and beware of the supplication of the wronged person, for there is no barrier between it and Allah."
قال رسول الله ﷺ لمعاذ بن جبل حين بعثه إلى اليمن: إنك ستأتي قوما أهل كتاب، فإذا جئتهم فادعهم إلى أن يشهدوا أن لا إله إلا الله وأن محمدا رسول الله، فإن هم أطاعوا لذلك فأخبرهم أن الله قد فرض عليهم خمس صلوات في كل يوم وليلة، فإن هم أطاعوا لذلك فأخبرهم أن الله قد فرض عليهم صدقة تؤخذ من أغنيائهم فترد على فقرائهم، فإن هم أطاعوا لذلك، فإياك وكرائم أموالهم، واتق دعوة المظلوم، فإنه ليس بينه وبين الله حجاب.
Bukhari related it in the Book of Military Expeditions (4347), and Muslim in the Book of Faith (19), both from the hadith of Zakariya bin Ishaq, who said, Yahya bin Abdullah bin Sayfi told me, from Abu Mabad, the freed slave of Ibn Abbas, from Ibn Abbas, and he narrated it, and their wording is identical.