Mu'adh bin Anas (May Allah be pleased with him) reported:
Messenger of Allah ﷺ said, "He who has taken food and says at the end: 'Al- hamdu lillahi-lladhi at'amani hadha, wa razaqanihi min ghairi haulin minni wa la quwwatin (All praise is due to Allah Who has given me food to eat and provided it without any endeavour on my part or any power),' all his past sins will be forgiven."

At-Tirmidh i].

وعن معاذ بن أنس رضى الله عنه قال: قال رسول الله ﷺ: "من أكل طعاماً فقال: الحمد الله الذي أطعمني هذا، ورزقنيه من غير حول منى ولا قوةٍ، غفر له ما تقدم من ذنبه" .