The Prophet of Allah ﷺ was on one of his journeys with Muaz bin Jabal riding behind him, with nothing between them but the rear of the saddle, when the Prophet of Allah ﷺ said, "Muaz bin Jabal."Muaz replied, "At your service, Messenger of Allah, and at your pleasure."He rode on for a while, then said, "Muaz bin Jabal."Muaz replied, "At your service, Messenger of Allah, and at your pleasure."The Prophet asked, "Do you know what is the right of Allah over His servants?"Muaz answered, "Allah and His Messenger know best."The Prophet said, "The right of Allah over His servants is that they worship Him and associate nothing with Him."Then he asked, "Do you know what is the right of the servants over Allah when they do that?"Muaz answered, "Allah and His Messenger know best."The Prophet said, "Their right over Allah
is that He will not punish them."
حدثنا حسين في تفسير شيبان عن قتادة
أن نبي الله ﷺ كان في بعض أسفاره ورديفه معاذ بن جبل ليس بينهما غير آخرة الرحل إذ قال نبي الله ﷺ يا معاذ بن جبل قال لبيك يا رسول الله وسعديك ثم سار ساعة ثم قال يا معاذ بن جبل قال لبيك يا رسول الله وسعديك قال هل تدري ما حق الله عز وجل على العباد قال الله ورسوله أعلم قال فإن حق الله على العباد أن يعبدوه ولا يشركوا به شيئا قال فهل تدري ما حق العباد على الله إذا هم فعلوا ذلك قال الله ورسوله أعلم قال فإن حقهم على الله عز وجل أن لا يعذبهم
Its chain of transmission is sahih. It is found in Bukhari 8/130, in the chapter on Riqaq, on one who struggles against himself in obedience to Allah, and in Muslim 1/55, in the chapter on Faith, as evidence that whoever dies upon monotheism enters Paradise without doubt.