Albert Barnes Commentary 2 Chronicles 24:21

"And they conspired against him, and stoned him with stones at the commandment of the king in the court of the house of Jehovah." — 2 Chronicles 24:21 (ASV)

In the court of the house of the Lord - "Between the altar and the Temple," or directly in front of the temple porch, if it is this Zechariah of whom our Lord speaks (Matthew 23:35). A horror of the impious deed long possessed the Jews, who believed that the blood could not be effaced but continued to bubble on the stones of the court, like newly shed blood, until Nebuzaradan entered the temple just before its destruction.