The Command to answer and obey Allah and His Messenger
Allah commands;
يَا أَيُّهَا الَّذِينَ امَنُواْ اسْتَجِيبُواْ لِلّهِ وَلِلرَّسُولِ إِذَا دَعَاكُم لِمَا يُحْيِيكُمْ
O you who believe! Answer Allah and (His) Messenger when he (the Messenger) calls you to that which will give you life,
Al-Bukhari said,
"(
اسْتَجِيبُواْ
Answer), obey, (
لِمَا يُحْيِيكُمْ
that which will give you life) that which will make your affairs good."
Al-Bukhari went on to narrate that Abu Sa`id 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,
مَا مَنَعَكَ أَنْ تَأْتِيَنِي أَلَمْ يَقُلِ اللَّهُ
What prevented you from answering me?
Has not Allah said;
يَا أَيُّهَا الَّذِينَ امَنُواْ اسْتَجِيبُواْ لِلّهِ وَلِلرَّسُولِ إِذَا دَعَاكُم لِمَا يُحْيِيكُمْ
(O you who believe! Answer Allah and (His) Messenger when he calls you to that which will give you life).'
He then said;
لَاأُعَلِّمَنَّكَ أَعْظَمَ سُورَةٍ فِي الْقُرانِ قَبْلَ أَنْ أَخْرُج
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,
الْحَمْدُ للَّهِ رَبِّ الْعَـلَمِينَ
All the praises and thanks are to Allah, the Lord of all that exists... (1;1-6)
هِيَ السَّبْعُ الْمَثَانِي
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,
يَا أَيُّهَا الَّذِينَ امَنُواْ اسْتَجِيبُواْ لِلّهِ وَلِلرَّسُولِ إِذَا دَعَاكُم لِمَا يُحْيِيكُمْ
(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,
وَاعْلَمُواْ أَنَّ اللّهَ يَحُولُ بَيْنَ الْمَرْءِ وَقَلْبِهِ
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, Sa`id, Ikrimah, Ad-Dahhak, Abu Salih Atiyyah, Muqatil bin Hayyan and As-Suddi.
In another report from Mujahid, he commented;
يَحُولُ بَيْنَ الْمَرْءِ وَقَلْبِهِ
(...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,
يَا مُقَلِّبَ الْقُلُوبِ ثَبِّتْ قَلْبِي عَلَى دِينِك
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,
نَعَمْ إِنَّ الْقُلُوبَ بَيْنَ إِصْبَعَيْنِ مِنْ أَصَابِعِ اللهِ تَعَالَى يُقَلِّبُهَا
Yes, for the hearts are between two of Allah's Fingers, He changes them (as He wills)."
This is the same narration recorded by At-Tirmidhi in the Book of Qadar in his Jami (Sunan), and he said, "Hasan."
Imam Ahmad recorded that An-Nawwas bin Sam`an Al-Kilabi said that he heard the Prophet saying,
مَا مِنْ قَلْبٍ إِلاَّ وَهُوَ بَيْنَ أُصْبُعَيْنِ مِنْ أَصَابِعِ الرَّحْمَنِ رَبِّ الْعَالَمِينَ إِذَا شَاءَ أَنْ يُقِيمَهُ أَقَامَهُ وَإِذَا شَاءَ أَنْ يُزِيغَهُ أَزَاغَه
Every heart is between two of the Fingers of the Most Beneficent (Allah), Lord of all that exists, if He wills, He makes it straight, and if He wills, He makes it stray.
And he said;
يَا مُقَلِّبَ الْقُلُوبِ ثَبِّتْ قَلْبِي عَلَى دِينِك
O You Who changes the hearts! keep my heart firm on Your religion!
And he would say;
وَالْمِيزَانُ بِيَدِ الرَّحْمنِ يَخْفِضُهُ وَيَرْفَعُه
The Balance is in the Hand of Ar-Rahman, He raises and lowers it.
This was also recorded by An-Nasa'i and Ibn Majah.
وَأَنَّهُ إِلَيْهِ تُحْشَرُونَ
And verily to Him you shall (all) be gathered