Explaining the aayah:
“And those who say, ‘Our Lord, grant us from among our wives and offspring comfort to our eyes and make us a leader for the righteous.’” [Furqaan: 25:74]
Ibn al-Qayyim said, ‘And Al-Farraa said, ‘He [i.e., Allaah, the Most High] said, ‘a leader’ and didn’t say, ‘leaders’ in the same way that He said, “[Both of you, i.e., Musaa and Haroon] Go to Pharaoh and say, ‘We are a messenger of the Lord of the worlds,’” [Shu’araa 26:16] and He didn’t say, ‘two messengers,’ and this is the singular through which the plural is meant.’’
Ibn al-Qayyim, commenting on this explanation of al-Farraa went on to say, ‘And this is the best of the sayings [explaining this point], except that it needs further elucidation.
And that [elucidation] is that the believers, all of them, are on one path, and their deity is one, and they are the followers of one Book, and one Prophet, slaves of One Lord, so their religion is one, and their Prophet is one, and their Book is one, and their deity is One–so it is as though all of them are one Imaam for those who come after them.’
Risaalatu Ibn al-Qayyim Ilaa Ahad Ikhwaanihi, [Ibn al-Qayyim’s Letter to One of His Brothers], pp. 14-15.