On this account of the Baptist's mode of preaching, see the notes on Matthew 3:7-11 (note).

O generation.

Genesis 3:15 And I will put enmity between you and the woman, and between your seed and her seed; it shall bruise your head...

Psalm 58:4,5 Their poison is like the poison of a serpent: they are like the deaf adder that stops her ear...

Isaiah 59:5 They hatch cockatrice' eggs, and weave the spider's web: he that eats of their eggs dies...

Matthew 3:7-10 But when he saw many of the Pharisees and Sadducees come to his baptism, he said to them, O generation of vipers...

Matthew 23:33 You serpents, you generation of vipers, how can you escape the damnation of hell?

John 8:44 You are of your father the devil, and the lusts of your father you will do. He was a murderer from the beginning...

Acts 13:10 And said, O full of all subtlety and all mischief, you child of the devil, you enemy of all righteousness...

1 John 3:8 He that commits sin is of the devil; for the devil sins from the beginning. For this purpose the Son of God was manifested...

to flee.

1 Thessalonians 1:10 And to wait for his Son from heaven, whom he raised from the dead, even Jesus, which delivered us from the wrath to come.

Hebrews 6:18 That by two immutable things, in which it was impossible for God to lie, we might have a strong consolation...

John's Rebuke of Herod.
Preached May 15, 1853. JOHN'S REBUKE OF HEROD. "But Herod the tetrarch, being reproved by him for Herodias, his brother Philip's wife, and for all the evils which Herod had done, added yet this above all, that he shut up John in prison,"--Luke iii. 19, 20. The life of John the Baptist divides itself into three distinct periods. Of the first we are told almost nothing, but we may conjecture much. We are told that he was in the deserts till his showing unto Israel. It was a period probably, in which, …
Frederick W. Robertson—Sermons Preached at Brighton

A New Age and New Standards
As the Kingdom Comes Ethical Standards Must Advance Every approximation to the Reign of God in humanity demands an advance in the social relations of men, that is, an advance in ethics. Every really epochal advance must have it or slip back. There must be, first, better obedience to the moral principles already recognized and accepted by society; second, an expansion of the sway of ethical duty to new fields and wider groups of humanity; and third, a recognition of new duties and the assimilation …
Walter Rauschenbusch—The Social Principles of Jesus

Luke.
Lucas, Evangelii el medicinae munera pandens; Artibus hinc, illinc religione, valet: Utilis ille labor, per quem vixere tot aegri; Utilior, per quem tot didicere mori!" Critical and Biographical Schleiermacher: Ueber die Schriften des Lukas. Berlin, 1817. Reprinted in the second vol. of his Sämmtliche Werke, Berlin, 1836 (pp. 1-220). Translated by Bishop Thirlwall, London, 1825. James Smith (of Jordanhill, d. 1867): Dissertation on the Life and Writings of St. Luke, prefixed to his Voyage and …
Philip Schaff—History of the Christian Church, Volume I