مَا قُلْتُ لَهُمْ إِلَّا مَآ أَمَرْتَنِى بِهِۦٓ أَنِ ٱعْبُدُوا۟ ٱللَّهَ رَبِّى وَرَبَّكُمْ ۚ وَكُنتُ عَلَيْهِمْ شَهِيدًا مَّا دُمْتُ فِيهِمْ ۖ فَلَمَّا تَوَفَّيْتَنِى كُنتَ أَنتَ ٱلرَّقِيبَ عَلَيْهِمْ ۚ وَأَنتَ عَلَىٰ كُلِّ شَىْءٍ شَهِيدٌ Qur’an Al-Ma'ida (5:117)M a qultu lahum ill a m a amartanee bihi ani oAAbudoo All a ha rabbee warabbakum wakuntu AAalayhim shaheedan m a dumtu feehim falamm a tawaffaytanee kunta anta a l rraqeeba AAalayhim waanta AAal a kulli shayin shaheed un
The definite article in anta'r-raqib expresses God's exclusiveness in His function as raqib ("keeper"), and can only be rendered by an interpolation of the (elliptically implied) word "alone". Similar expressions relating to God are very often met with in the Qur'an - e.g., at the end of the next verse.
This refers to the ascension of Jesus Christ. See footnote for 3:54.
Jesus here acknowledges that he was mortal, and that his knowledge was limited like that of a mortal.