أَحَطتُ بِمَا لَمْ تُحِطْ بِهِ (I have discovered what you did not - 27:22). That is, the hoopoe. said while offering its excuse that it knew something which he did not know. What it meant was that it had brought information, which he (Sulaiman علیہ السلام) did not know before.
The prophets do not have the knowledge of the unknown
Imam Qurtubi has deduced from this incident that the prophets do not have the knowledge of the unseen (` Ilm ul-ghayb), so that they could know all about everything. It is quite evident from this verse.
وَجِئْتُكَ مِن سَبَإٍ بِنَبَإٍ يَقِينٍ
"And have brought to you a sure information from Saba' (Sheba) ". 27:22
Saba' (Sheba) (سَبَاء) is a well-known city of Yemen, and its other name is Ma'arib (مَآرِب). The distance between San` a', the capital of Yemen, and Saba' is three day's journey.
Is it proper for a junior to say to his senior that he knows more than him?
On the basis of this conversation by the hoopoe, some people have deduced that it is appropriate for a pupil to say to his teacher or for a common man to say to a knowledgeable person that he knows more than the latter on the subject, provided he is absolutely confident that his knowledge on that subject is really more than others. But it is argued in Ruh ul-Ma’ ani that such an assertion before the elders and scholars is against the etiquettes, and should be avoided. This argument, however, does not apply to the conversation of the hoopoe, because it made that statement to save itself from the punishment and to justify its excuse for the absence. The hoopoe actually wanted to place before Sulaiman (علیہ السلام) the exact position, so that he could understand the reason for its absence. In such situations it is not improper if something is said against the normal etiquettes.