How do we reconcile the Hadith: "Indeed, there are among the servants of Allah those who, were they to swear by Allah, He would fulfill their oath," with the story of Sulaiman (peace be upon him) who swore to go around to ninety women but his oath was not fulfilled, knowing that prophets are the best of people and more deserving that Allah should fulfill their oaths?

The meaning of "If he were to swear by Allah, Allah would fulfill it" is that if he were to swear that something would happen, Allah would make it happen as an honor to him, or it is a metaphor for the acceptance of his supplication. And the Prophet of Allah, Solomon (peace be upon him), was not pardoned for omitting the mention of "if Allah wills" and the exception in his oath when he said: "I will go around tonight to ninety women." This resulted in his wish not being fulfilled, even though Prophets are more worthy of Allah fulfilling their oaths than others. This is because he (peace be upon him) was a Prophet who was looked up to and emulated. His omission, due to forgetfulness, was an indication that those who are close to Allah, among the pious and righteous, may not be pardoned for omitting something that others would not be reprimanded for if they omitted it. This was a form of discipline from Allah for His Prophets and chosen ones.