Because the Bible commands that both ministerial servants and elders attain a high moral and spiritual standard before they are appointed to serve.
لِنَأْخُذْ مَثَلًا ٱخْتِبَارَ تشاد ٱلَّذِي تَرَعْرَعَ فِي بَيْتٍ مُنْقَسِمٍ دِينِيًّا وَعُيِّنَ مُؤَخَّرًا لِيَخْدُمَ شَيْخًا .‏