Is it permissible to say "Allah and His Messenger know best" concerning matters of the unseen, taking into account that the Messenger's knowledge ceased with his death?

It is not said that the Messenger, peace and blessings be upon him, knows the Unseen except for what Allah has taught him. For the knowledge of the Unseen is exclusive to Allah Almighty alone, and the Messenger knows nothing of it except for what Allah has revealed to him.