But the Hebrew does use the plural of respect LIke in the book of Psalms.
In Islam, we believe that all the Muslims are unanimously agreed that the Prophets (peace be upon them) – especially Muhammad pbuh – are infallible and protected from error in that which they conveyed from Allah.
1 – Infallibility in conveying the message
2 – Infallibility from human error such as major sins like adultery etc.
The Prophets were infallible in conveying the message from Allah. They did not conceal anything that Allah had revealed to them, and they did not add anything from themselves. Allah says, “O Messenger (Muhammad)! Proclaim (the Message) which has been sent down to you from your Lord. And if you do not, then you have not conveyed His Message. Allah will protect you from mankind”
al-Maa'idah 5:67
“And if he (Muhammad) had forged a false saying concerning Us (Allah),
We surely would have seized him by his right hand (or with power and might),
And then We certainly would have cut off his life artery (aorta),
And none of you could have withheld Us from (punishing) him”
al-Haaqqah 69:44-47
All the Muslims are unanimously agreed that the Prophets (peace be upon them) are infallible and protected from error in that which they conveyed from Allah.
The verses which point to the Prophethood of the Prophets indicate that they are infallible with regard to the message that they convey from Allah, so what they convey from their Lord can only be true. This is the meaning of Prophethood and this implies that Allah tells [the Prophet] of the unseen and he tells the people of the unseen. So the Messenger is commanded to call people and to convey the message to them.
With regard to the Prophets as people, they may make mistakes.
1 –They do not commit major sins
With regard to major sins, the Prophets do not commit major sins at all, and they are protected from such major sins both before their missions began or afterwards.
The Prophets were infallible in conveying the message from Allah, so their words could not be but true and they did not make any mistake, whether deliberate or otherwise, in conveying the message.
They were also infallible and protected from committing major sins such as zina (adultery) and theft.
They were also infallible and protected from committing minor sins that are indicative of baseness, such as stealing a morsel of food or giving short measure.
Some of them may have made mistakes in minor issues that are not indicative of baseness, but they did not persist in that; rather Allah, may He be exalted, pointed that out to them and drew their attention to that, so they corrected their mistakes.