As for those who strive in Us,
We surely guide them to Our paths (Quran)
Read the translation of the underlined narration, which is given bellow
"...Narrating Ibn Abbas, he said;
"Allah has revealed to Muhammed peace and prayers of Allah be upon him and his family, "I have killed for Yahya ibn Zakariya’s (retaliation) seventy thousand (men) and I will be killing for the retaliation of the son of your daughter (Imam Hussain) seventy thousand and seventy thousand" "
Footnote: This is correct chain of reference hadeeth however they (Bukhari and Muslim) did not narrate it. Al Dhahabi agreed the narration to be correct based on the conditions of Muslim in his “Talkhis”. Al-Dhahabi mentioned: "This is a hadeeth whose chain of narration is clean, but its content is unacceptable"
Source: Al-Mustadrak Ala Sahihain. Vol. 3, Pg. # 195 - 196. H. # 4822.
Remark: Just keep in mind that the number "70" in Arabic is somtimes used to refer to unidentified big number...So the number of those criminals who will be killed in revenge of imam Hussain (a.s) could be vastly larger than the given number...
Available From: "Revisiting The Salaf" Blog, with some editions.