لِّيَعۡلَمَ أَن قَدۡ أَبۡلَغُواْ رِسَٰلَٰتِ رَبِّهِمۡ وَأَحَاطَ بِمَا لَدَيۡهِمۡ وَأَحۡصَىٰ كُلَّ شَيۡءٍ عَدَدَۢا ٢٨
That he [i.e., Muḥammad (ﷺ)] may know1 that they have conveyed the messages of their Lord; and He has encompassed whatever is with them and has enumerated all things in number.
Translation: Saheeh International (English)
1 This phrase may also be read: "So He [i.e., Allāh] may make evident."
Each word's meaning and sound
This is done in the hope that the messenger may know that the messengers before him had conveyed the messages of their Lord that He had instructed them to convey because of the care that Allah gave to it. Allah’s knowledge surrounds whatever is with the angels and messengers. Nothing of that is hidden from Him. He has counted the number of everything, so that nothing is hidden from Him, may He be glorified.
Al-Mukhtasar in interpreting the Noble Quran