Majma al-Zawaid — Hadith 16665

Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Asqalan is one of the two brides. From there, on the Day of Resurrection, seventy thousand people will be raised who will not be taken to account, and from there 50 thousand martyrs will be raised who will go as a delegation to the presence of Allah Almighty. And there will be rows of those martyrs whose heads will be cut off and held in their hands, blood gushing from their veins, and they will say: 'Our Lord! Grant us what You promised us through Your Messengers; indeed You do not break the promise.' The Lord will say: 'My servants have spoken the truth; wash them in the River of al-Baydah.' When they come out of it they will be clean and shining white, and then they will stay wherever they wish in Paradise."
Ahmad recorded it; its chain contains a narrator, Abu Iqal Hilal bin Zayd bin Yasar, whom Ibn Hibban declared thiqah (trustworthy) and the majority declared da'if (weak); the rest of its narrators are thiqat (trustworthy). There is a difference of opinion about the narrator Isma'il bin Ayyash.