بسم الله الرحمان الرحيم
"Someone saw Hadhrat Mahmudul Hasan Deobandi in a dream. He asked about his condition. Hadhrat Mahmudul Hasan replied, 'Once, there was too much salt in the food. I ate the food without the slightest complaint. On the basis of this act, I was forgiven."
[Malfoozhaat Maulana Ashraf Ali Thanvi, v.4, p.14]
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The reason behind this is that abstaining from criticising food is from the Sunnah. Rasoolullaah Sallallaahu `Alayhi wa Sallam never criticised any food. If he liked it, he would eat it. If he did not like it, he would not eat it. Never were there any complaints.
Shaykhul Hind (Maulana Mahmudul Hasan) had abstained from criticising the food in order to follow the Sunnah. Shaykhul Hind was one of the `Ulamaa who were staunchest in adhering to every Sunnah of Rasoolullaah Sallallaahu `Alayhi wa Sallam, even those people deem small and insignificant.