It is narrated from Sayyiduna Wathilah (may Allah be pleased with him); he said: A questioner asked the Messenger of Allah (peace and blessings be upon him): Why is it that on Friday the call to prayer is given at midday, when you (peace and blessings be upon him) have forbidden it on the other days? He (peace and blessings be upon him) said: "Allah Almighty kindles Hell every day at midday, and on Friday He lets it die down (cools it)."
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18364