I used to attribute perfection only to God and I apologize for my inattention because in the following part of the verse 5 in surah Al-Ma’ida it’s mentioned that God perfected the Islamic religion.

الْيَوْمَ أَكْمَلْتُ لَكُمْ دِينَكُمْ وَأَتْمَمْتُ عَلَيْكُمْ نِعْمَتِي وَرَضِيتُ لَكُمُ الْإِسْلَامَ دِينًا ۚ

This day I have perfected for you your religion and completed My favor upon you and have approved for you Islam as religion.