(a) Abu Uthman al-Nahdi (may Allah have mercy on him) narrates: I prayed behind Sayyiduna Umar (may Allah be pleased with him) for six years, and he used to recite qunut.
(b) Sulayman al-Taymi (may Allah have mercy on him) transmitted this narration from Abu Uthman (may Allah have mercy on him), that Sayyiduna Umar (may Allah be pleased with him) recited qunut in the morning prayer.
(c) Likewise, Abu Rafi' (may Allah have mercy on him) narrated it from Sayyiduna Umar (may Allah be pleased with him), as we shall mention, in sha' Allah.
(d) In a matter of this kind, the word of the one who both witnessed and remembered is what counts, not the word of the one who neither witnessed nor remembered. 'Wa billahi al-tawfiq' (And success comes only from Allah).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3114