Is washing the hands after waking from sleep at night a recommended practice or obligatory?

Question:
May Allah reward you, Your Eminence, father. The questioner asks: Can it be said of the one who did not wash his hands after sleeping at night, which invalidates his ablution, that he left the preferred action, and that the water does not become invalid because he is not certain of its impurity, and the rule is that certainty is not removed by doubt?

Answer:
This is a disagreement regarding the evidence. He held the view of those among the scholars who said that washing the hands after sleep is a recommended practice (sunnah). But this contradicts the evidence. The evidence is that washing them is obligatory due to the command of the Messenger (peace and blessings be upon him) to do so, and there is no factor diverting from that. It has no factor diverting it from being obligatory. So the one who claims it is for recommendation must bring the evidence that diverts it from that. Yes.