O Lord, how long shall I cry - The prophet feels himself strongly excited against the vices which he beheld; and which, it appears from this verse, he had often declaimed against, but in vain; the people continued in their vices, and God in his longsuffering.
Habakkuk begins his prophecy under a similar feeling, and nearly in similar words, as Juvenal did his Satires: -
Semper ego auditor tantum?
Nunquamne reponam?
Vexatus toties rauci Theseide Codri?
Sat. 1:1.
"Shall I always be a hearer only?
Shall I never reply?
So often vexed?"
Of violence - The most unlawful and outrageous acts.

The burden which Habakkuk the prophet did see. This prophecy is called a "burden", or something took up and carried, being what the prophet received from the Lord, and went with to the people of the Jews, and was a heavy burdensome prophecy to them; declaring the calamities that should come upon them by the Chaldeans, who would invade their land, and carry them captive; and Habakkuk, that brought this account, is called a "prophet", to give the greater sanction to it; and it was what he had in vision from the Lord represented unto him, and therefore should be credited. Abarbinel inquires why Habakkuk should be called a prophet, when none of the lesser prophets are, excepting Haggai and Zechariah; and thinks the reason of it is, to give weight to his prophecy, since it might be suspected by some whether he was one; there being none of those phrases to be met with in this prophecy as in others, as "the word of the Lord came", &c. or "thus saith the Lord".
The burden which Habakkuk the prophet did see. This prophecy is called a "burden", or something took up and carried, being what the prophet received from the Lord, and went with to the people of the Jews, and was a heavy burdensome prophecy to them; declaring the calamities that should come upon them by the Chaldeans, who would invade their land, and carry them captive; and Habakkuk, that brought this account, is called a "prophet", to give the greater sanction to it; and it was what he had in vision from the Lord represented unto him, and therefore should be credited. Abarbinel inquires why Habakkuk should be called a prophet, when none of the lesser prophets are, excepting Haggai and Zechariah; and thinks the reason of it is, to give weight to his prophecy, since it might be suspected by some whether he was one; there being none of those phrases to be met with in this prophecy as in others, as "the word of the Lord came", &c. or "thus saith the Lord".
Habakkuk 1:2

hab 1:2
hab 1:2
hab 1:2O Lord, how long shall I cry, and thou wilt not hear!.... The prophet having long observed the sins and iniquities of the people among whom he lived, and being greatly distressed in his mind on account of them, had frequently and importunately cried unto the Lord to put a stop to the abounding of them, that the people might be brought to a sense of their sins, and reform from them; but nothing of this kind appearing, he concludes his prayers were not heard, and therefore expostulates with the Lord upon this head:

even cry unto thee of violence, and thou wilt not save! either of violence done to himself in the discharge of his office, or of one man to another, of the rich to the poor; and yet, though he cried again and again to the Lord, to check this growing evil, and deliver the oppressed out of the hands of their oppressors, it was not done; which was matter of grief and trouble to him.

violence . . . Why dost thou show me iniquity?--Similar language is used of the Chaldeans (Hab 1:9, Hab 1:13), as here is used of the Jews: implying, that as the Jews sinned by violence and injustice, so they should be punished by violence and injustice (Pro 1:31). Jehoiakim's reign was marked by injustice, treachery, and bloodshed (Jer 22:3, Jer 22:13-17). Therefore the Chaldeans should be sent to deal with him and his nobles according to their dealings with others (Hab 1:6, Hab 1:10-11, Hab 1:17). Compare Jeremiah's expostulation with Jehovah, Jer 12:1; Jer 20:8; and Job 19:7-8.