"They shall possess no intercession, except for him who has taken a covenant with the Most Merciful." Some said the covenant is: Monotheism (Tawhid).
﴿لَا يَمْلِكُونَ الشَّفَاعَةَ إِلا مَنِ اتخذ عِنْد الرَّحْمَن عهدا﴾ قَالَ بَعضهم الْعَهْد: التَّوْحِيد.