Luke 11:51

blood of Zacharias--Probably the allusion is not to any recent murder, but to Ch2 24:20-22, as the last recorded and most suitable case for illustration. And as Zacharias' last words were, "The Lord require it," so they are warned that "of that generation it should be required."

In this chapter, I. Christ teaches his disciples to pray, and quickens and encourages them to be frequent, instant, and importunate in prayer (Luk 11:1-13). II. He fully answers the blasphemous imputation of the Pharisees, who charged him with casting out devils by virtue of a compact and confederacy with Beelzebub, the prince of the devils, and shows the absurdity and wickedness of it (Luk 11:14-26). III. He shows the honour of obedient disciples to be greater than that of his own mother (Luk 11:27, Luk 11:28). IV. He upbraids the men of that generation for their infidelity and obstinacy, notwithstanding all the means of conviction offered to them (Luk 11:29-36). V. He severely reproves the Pharisees and consciences of those that submitted to them, and their hating and persecuting those that witnessed against their wickedness (v. 37-54).

11:51 from the murder of Abel to the murder of Zechariah: Abel’s murder by his brother Cain was the first murder recorded in the Old Testament (Gen 4:8). The stoning of Zechariah, son of Jehoiada (2 Chr 24:20-22) was the last, since Chronicles is the last book in the Hebrew Bible.