In The Name of Allaah, The Most Merciful The Bestower of Mercy
Imaam as-Saa’di (rahimahullaah}said: ”He who deceives the Muslims in their Religious and Worldly Affairs is not from them”
Amongst the benefits of Naseehah (sincere advice) is safety from deceit. Indeed, he who deceives the Muslims in their Religious and Worldly Affairs is not from them. Deceit is from the most repugnant of ugly traits as it relates to (fulfilling) the rights of a relative and the non-relative, the (rights) of the one in opposition (to you) and the one in agreement. The Great Qur’aan calls to this quality, which is from the best of qualities. It (naseehah-sincere advice) is that which the Religion of Islaam is founded and upon which its structure is made to stand firm, and through which its superiority over everything else is manifested. Indeed, giving sincere advice to every individual is commended by the sharee-ah, the sound intellect and the natural disposition, and that which is in opposition to it is repulsive to the sharee-ah, the intellect and the natural disposition.
(Source:Fathul Raheemil Malikil Allaam Fee Ilmil Aqaa-id Wat-tawheed, Wal Akhlaaq, Wal Ahkaam. Page: 98)