Soundness of the hadeeth Hadeeth “Sincerity is one of My secret blessings”
Question

What is the soundness of the hadeeth qudsi (prophetic narration in which the Prophet attributes what is said to Allah), “Sincerity is one of My secret blessings, which I have instilled in the heart of those whom I love among My slaves?”
Praise be to Allah.This hadeeth is da’eef jiddan (very weak) or mawdoo’ (fabricated). 
It was narrated by al-Qazweeni in his Musalsalat, as al-Iraqi said in Takhreej Ihya ‘Uloom al-Deen, 4/365, from the hadeeth of Hudhayfah (may Allah be pleased with him). But its isnad (chain of narrators) includes Ahmad ibn ‘Ata al-Hujaymi and ‘Abd al-Wahid ibn Zayd, both of whom are matrook (i.e., their hadeeth is not accepted). 
It was also narrated by al-Daylami in Musnad al-Firdaws, 3/187, from ‘Ali and Ibn ‘Abbas (may Allah be pleased with them). 
Al-Hafiz ibn Hajar said in Fath al-Bari, 4/109, (it is) a wahin jiddan hadeeth (i.e., very flimsy)