What was engraved on the seal of the Prophet (peace and blessings be upon him) and on the seal of Abu Bakr (may Allah be pleased with him)?

The engraving on the Prophet's ring (peace and blessings be upon him) was "Muhammad Rasul Allah" (Muhammad is the Messenger of Allah), on three lines, with each word on a separate line. As for the engraving on Abu Bakr's ring, it was said to be "Ni'ma al-Qadir Allah" (How excellent is Allah, the Omnipotent), and it was also said to be "Abd Dhaleel li Rabb Jaleel" (A humble servant to a Majestic Lord), with the first opinion being more accurate.