[22].Surah Al-Hajj [The Pilgrimage]: Ayat 37-38

Ayat 37. It is neither their meat nor their blood that reaches Allah, but it is piety from you that reaches Him. Thus have We made them subject to you that you may magnify Allah for His Guidance to you. And give glad tidings (O Muhammad  [SAWW](PBUH) to the Muhsinun (doers of good).

Ayat 38. Truly, Allah defends those who believe. Verily! Allah likes not any treacherous ingrate to Allah [those who disobey Allah but obey Shaitan (Satan)].

[Tafseer] The essence of sacrifice has been explained in "No one should suppose that meat or blood is acceptable to the One True God. It was a Pagan fancy that Allah could be appeased by blood sacrifice. But Allah does accept the offering of our hearts, and as a symbol of such offer, some visible institution is necessary. He has given us power over the brute creation, and permitted us to eat  meat, but only if we pronounce His name at the solemn act of taking life, for without this solemn invocation, we are apt to forget the sacredness of life. We should be grateful to Allah for His guidance in this matter, in which many Peoples have gone wrong, and we should proclaim the true doctrine, so that virtue and charity may increase among men. Verily Allah will defend (from ill) those who believe: verily, Allah loved not any that is a traitor to faith, or show ingratitude.

Hazrat Wabisah bin Ma`bad (May Allah be pleased with him) reported: I went to Messenger of Allah [SAWW](PBUH) and he asked me, "Have you come to inquire about piety?'' I replied in the affirmative. Then he said, "Ask your heart regarding it. Piety is that which contents the soul and comforts the heart, and sin is that which causes doubts and perturbs the heart, even if people pronounce it lawful and give you verdicts on such matters again and again.''

[Masnad Ahmad, Imam Ahmad Hadith # 228/4]. 

Lesson : as mentioned above in Surah Al-Hajj Ayat 38."Truly, Allah defends those who believe." There are two points about this Hadith. First, it is one of the miracles of Messenger of Allah [SAWW](PBUH) who discovered the nature of the question before it was put to him. Second, man's heart is the biggest guide to him and he, therefore, should keep his heart illuminated with the light of Faith so as to continue receiving guidance from it.