The preceding verses spoke of the obstinate ignorance of the disbelievers who rejected the true Faith, despite all the clear signs given to them by Allah. This could be a source of grief to the Holy Prophet ﷺ as he was highly considerate and the greatest well-wisher of the mankind. The verse 186 provides him with a consolation saying that whomsoever Allah leaves wandering in his ignorance and lets him go on with his evil deeds can never be guided by any one and Allah leaves him at the mercy of his abject desires. That is to say, the Holy Prophet ﷺ has done his duty by conveying the message of Allah as explicitly as was possible, and that their rejection of the true faith was not for any of his faults.
Among the themes of this Surah (Al-A` raf) three topics are of great importance: the unity of Allah (Tauhid), the Prophethood (Risalah) and the life in the Hereafter (آخرَت). These three principles are, in fact, the mainstay of the whole edifice of Islam. Exposition of the first two principles, the Tauhid and the Risalah have been provided in the foregoing verses.