In the second (52) of the two verses cited above, Sayyidna Yusuf (علیہ السلام) has himself pointed out to two considerations implied in the way he acted and in the option of delaying his release.
The first consideration was: ذٰلِكَ لِيَعْلَمَ اَنِّىْ لَمْ اَخُنْهُ بِالْغَيْبِ. It means: I delayed my release so that the ` Aziz of Misr comes to know for sure that I did not betray him in any way during his absence.
He was so concerned about making the ` Aziz of Misr become assured of his innocence because he thought it would be terrible if the ` Aziz of Misr continues to harbour doubts in his heart against him and suffer more from them when unable to say much after the royal honour has been conferred on him. If so, he would be displeased with the honour given to him and far more painful would be the silence he would have to maintain. Since, he had been his master when he lived with him, his pain was too much to bear for Sayyidna Yusuf (علیہ السلام) ، intrinsically gentle as he was. Then, it was equally obvious that once the ` Aziz of Misr came to believe in his innocence, people will stop talking by themselves.
The second consideration he mentions is: وَاَنَّ اللّٰهَ لَايَهْدِيْ كَيْدَ الْخَاۗىِٕنِيْنَ , that is, he asked for investigations to be made in order that people may know that Allah does not lead the guile of betrayers to success.
This statement could be taken to mean that an investigation would expose the betrayal of the betrayers and people would stand warned that betrayers are finally disgraced leaving a lesson for others to stay away from doing things like that in the future. Also possible here is another meaning, that is, had Sayyidna ~suf~ received the royal honours in the same climate of doubt, it may have occured to all watchers that it was not impossible to betray and be honoured at the same time. This would have distorted their faith in fidelity and would have driven away the distaste for betrayal from their hearts. However, it was because of these two considerations that Sayyidna Yusuf (علیہ السلام) did not favour his leaving the prison immediately after having received the message of his release. In fact, there was a touch of royal elegance in his manner when he demanded that his case be investigated first.