( وَمَا كَانَ اللَّهُ لِيُعَذِّبَهُمْ وَأَنتَ فِيهِمْ ) (But Allah would not punish them while you, [O Muhammad], are among them): This indicates that the Prophet Muhammad (saws) is a blessing for all people, believers and disbelievers, a blessing for the birds, the trees, the animals, the land, and everything  . Allah (swt) says:

  وَمَا أَرْسَلْنَاكَ إِلَّا رَحْمَةً لِّلْعَالَمِينَ

(And We have not sent you, [O Muhammad], except as a mercy to the worlds.) (Al-Anbiyaa: 107)

This verse reflects great honor and abundant favor from the Lord (swt) of the heavens and the earth to the Prophet (saws). Despite the fact of bringing Prophets from among their own people, and afflicting them with punishment, the presence of the Prophet Muhammad (saws) as the seal of the Prophets (PBUT) was a mercy to them. What an immense honor and favor bestowed upon the Prophet (saws).

( وَمَا كَانَ اللَّهُ مُعَذِّبَهُمْ وَهُمْ يَسْتَغْفِرُونَ ) (and Allah would not punish them while they seek forgiveness): As long as there is seeking forgiveness, Allah (swt) removes the punishment, and divine mercy is fulfilled. Therefore, there are two sources of protection from punishment: the presence of the Prophet Muhammad (saws), seeking forgiveness, clinging to the guidance of the Messenger of Allah (saws) as if he was present with us:

 وَمَا أَرْسَلْنَا مِن رَّسُولٍ إِلَّا لِيُطَاعَ بِإِذْنِ اللَّهِ ۚ وَلَوْ أَنَّهُمْ إِذ ظَّلَمُوا أَنفُسَهُمْ جَاءُوكَ فَاسْتَغْفَرُوا اللَّهَ وَاسْتَغْفَرَ لَهُمُ الرَّسُولُ لَوَجَدُوا اللَّهَ تَوَّابًا رَّحِيمًا

(And We did not send any messenger except to be obeyed by permission of Allah. And if, when they wronged themselves, they had come to you, [O Muhammad], and asked forgiveness of Allah and the Messenger had asked forgiveness for them, they would have found Allah Accepting of repentance and Merciful.) (An-Nisaa: 64)

When the Prophet (saws) was alive, and even after his ascent to the higher realm, we refer to his guidance and adhere to his (saws) command. This is the adherence to the guidance of the Messenger of Allah (saws) even after his passing away. When Allah (swt) says: (they had come to you, [O Muhammad], and asked forgiveness of Allah and the Messenger had asked forgiveness for them), the manner in which the Prophet (saws) asked for forgiveness for them is mentioned in the Hadith:

“My life is good for you; you relate to me, and I relate to you. My death is good for you; your deeds will be presented to me. Whatever good I see, I praise Allah for it, and whatever evil I see, I seek forgiveness for you.”[1]

[1] Musannad Al-Bazzar, no. 1925.