Mistake in Opening of Salah (Prayer)

2. Al-Husayn ibn Muhammad al-Ash’ariy has narrated from ‘Abd Allah ibn ‘Amir from Ali ibn Mahziyar from Fadalah from Aban from al-Fadl ibn ‘Abd al-Malik or ibn abu Ya‘fur who has said the following: “About a man who performs Salah (prayer) but forgets to say the opening Takbir (Allah is great beyond description) if Takbir (Allah is great beyond description) for Ruku‘ (bowing down on one’s knees) is sufficient. Abu ‘Abd Allah عليه السلام, has said, ‘It is not sufficient. He performs Salah (prayer) again when he finds out that he has not said the Takbir (Allah is great beyond description).”’