God Almighty said, addressing His Prophet, may God bless him and grant him peace:
(May Allah pardon you, [O Muhammad]; why did you give them permission [to remain behind]? [You should not have] until it was evident to you who were truthful and you knew [who were] the liars.) At-Tawbah 43.
May God forgive you:
God Almighty pardoned His Messenger before reproach in honor of him (Ibn Attiyya, Al-Razi, and Al-Qurtubi).
Why did you permit them: to sit and lag behind?
It is not understood from the verse that God Almighty wanted them to go out with the Prophet, may God’s blessings and peace be upon him, to wage jihad with him, as evidenced by what He said after two verses: (God hated their being send, so He kept them back (…) Had they gone forth with you, they would not have increased you except in confusion, and they would have been active among you, seeking [to cause] you fitnah. And among you are avid listeners to them. 47.
So that those who are truthful and those who are liars become clear to you :
The assessment is that: You should not have given them permission to leave you behind (al-Tabari) until it became clear to you… (See also: Ibn Ashour ).
Al-Tabari said: “They said: Ask the permission of the Messenger of God, may God bless him and grant him peace. If he authorizes you, then sit, and if he does not authorize you, then sit.”
Meaning: If he had not given them permission, they would have sat down and their hypocrisy and lies would be discovered, as God mentioned in the verse!
Why didn’t God protect him with revelation here?
I will dedicate a separate article to it, but it was explained to him after occurrence. And the explanation here is not related to permission for the hypocrites to sit, because they are sitting in any case, and God does not want them to go out. The explanation relates to the lies of the hypocrites.
Al-Qurtubi said: “Qatada and Amr bin Maymun said: There are two things that the Prophet, may God bless him and grant him peace, did and he was not commanded to do: His permission for a group of hypocrites to stay back, and he was not allowed to do anything without revelation, and he took the ransom from the captives, so God reprimanded him as you hear” (And see Also: Ibn Attiyya, and Al-Zamakhshari).
I say: That is, the second is the saying of the Most High: (It is not for a prophet to have captives [of war] until he inflicts a massacre [upon Allah ‘s enemies] in the land.) Al-Anfal 67.
Is it instructed from the verse that the Prophet may make ijtihad without revelation?
Al-Razi said: “Among the people are those who said: The Messenger, may God bless him and grant him peace, used to judge according to ijtihad in some facts. His evidence was the saying of Allah: (so, meditate, O you who have sight) Al-Hashr 2, an order for those with insight and diligence, and the Messenger was their master, so he was under this command, then they confirmed that with this verse
I say: I do not think that the permissibility of ijtihad of the Prophet, may God bless him and grant him peace, can be benefited from this verse because in this verse he was reprimanded, and God did not approve of his ijtihad. But it may be said: He strived and erred, and he has one reward, and God knows best.