This is a parable Allah has set forth. Hearts take from it in proportion to their certainty and their doubt. As for doubt, no deed profits along with it, but as for certainty, through it Allah benefits those who possess it. That is His saying, "As for the froth, it passes away as scum" [Rad 13:17], which is doubt, "but as for what benefits the people, it remains in the earth" [Rad 13:17], which is certainty. It is like jewelry placed in the fire, its pure metal is taken and its dross is left behind in the fire. In the same way, Allah accepts certainty and leaves doubt aside.
في قوله تعالى: {أنزل من السماء ماء فسالت أودية بقدرها}
فهذا مثل ضربه الله، احتملت منه القلوب على قدر يقينها وشكها، فأما الشك فلا ينفع معه العمل، وأما اليقين فينفع الله به أهله، وهو قوله: {فأما الزبد فيذهب جفاء}، وهو الشك{وأما ما ينفع الناس فيمكث في الأرض}، وهو اليقين، كما يجعل الحلي في النار، فيؤخذ خالصه، ويترك خبته في النار، فكذلك يقبل الله اليقين ويترك الشك.
No references are available.
Ibn Jareer Tabari narrated it in his Tafsir (12/498) from Muthanna, who said, Abdullah bin Salih narrated to us, Muawiya narrated to me, from Ali bin Abu Talha, from Ibn Abbas, and he related it.Its chain is hasan because of Ali bin Abu Talha, for even though he transmits from Ibn Abbas through an intermediary rather than directly, the intermediary is known, and he himself is truthful. Likewise, Abdullah bin Salih is hasan al-hadith.