24. O you who believe! Answer Allah and (His) Messenger when he (the Messenger) calls you to that which will give you life, and know that Allah comes between a person and his heart. And verily to Him you shall (all) be gathered.

Al-Bukhari said, "<Answer>, obey, <that which will give you life> that which will make your affairs good." Al-Bukhari went on to narrate that Abu Said bin Al-Mu'alla said, "I was praying when the Prophet passed by and called me, but I did not answer him until I finished the prayer. He said,
«What prevented you from answering me? Has not Allah said:
<O you who believe! Answer Allah and (His) Messenger when he calls you to that which will give you life>?»
He then said:
«I will teach you the greatest Surah in the Qur'an before I leave.»
When he was about to leave, I mentioned what he said to me. He said.
«All the praises and thanks are to Allah, the Lord of all that exists...» [1:1-6].
«Surely, it is the seven oft-repeated verses.»" Muhammad bin Ishaq narrated that Muhammad bin Jafar bin Az-Zubayr said that "Urwah bin Az-Zubayr explained this Ayah,
<O you who believe! Answer Allah and (His) Messenger when he calls you to that which will give you life, >
"Answer when called to war (Jihad) with which Allah gives you might after meekness, and strength after weakness, and shields you from the enemy who oppressed you."
Allah comes in between a Person and His Heart
Allah said,
<and know that Allah comes in between a person and his heart.>
Ibn 'Abbas commented, "Allah prevents the believer from disbelief and the disbeliever from faith." Al-Hakim recorded this in his Mustadrak and said, "It is Sahih and they did not record it." Similar was said by Mujahid, Said, 'Ikrimah, Ad-Dahhak, Abu Salih 'Atiyyah, Muqatil bin Hayyan and As-Suddi. In another report from Mujahid, he commented;
<... comes in between a person and his heart. >
"Leaves him without comprehension," As-Suddi said, "Prevents one self from his own heart, so he will neither believe nor disbelieve except by His leave." There are several Hadiths that conform with the meaning of this Ayah. For instance, Imam Ahmad recorded that Anas bin Malik said, "The Prophet used to often say these words,
«O You Who changes the hearts, make my heart firm on Your religion .»
We said, 'O Allah's Messenger! We believed in you and in what you brought us. Are you afraid for us?' He said,
«Yes, for the hearts are between two of Allah's Fingers, He changes them (as He wills).»"