(Ahsaab) 33 : 39
الَّذِينَ يُبَلِّغُونَ رِسَالَاتِ اللَّهِ وَيَخْشَوْنَهُ وَلَا يَخْشَوْنَ أَحَدًا إِلَّا اللَّهَ ۗ وَكَفَىٰ بِاللَّهِ حَسِيبًا

Those who are conveying the Message of Lord, fearing Him, and do fear none except Lord Allah; while Lord Allah is enough for reckoning. 

Messengers are deputed from among mankind to lead a practical life according to the Lord’s Message. They are bound to teach mankind the fact that there is no Deity except Lord Allah. That means Whom one can call without seeing, Whom one can seek for help, Whom one can seek refuge, upon Whom one can entrust, and to Whom only one has to submit his accountability of life in this world on the Day of Judgement. He is ‘Ilah’, the One and Only Deity Allah. Whoever is calling anyone other than the single Deity Lord, he is calling none except the rebel Satan and such are serving Satan as explained in verses 1: 4 and 4: 117. Since the Lord has created Heaven, earth, and all in between them, and He is taking care of them, He is the only authority to give rules and regulations as explained in verse 7: 54. Since the Lord is impartial, He will not inform anyone about his reckoning. Instead, He has fastened software on everyone’s neck and all his deeds and thoughts are being recorded in it. Also, it will be produced as an illuminating spread open Book on the Day of Judgement, and everyone’s reckoning will be done by reading that Book as explained in verses 17: 13-14. See explanation 3: 26-27; 5: 54, 67; 21: 24-25.