The first 6 verses are a call to repentance.
Zechariah 1:1 In the eighth month, in the second year of Darius, came the word of the L-RD unto Zechariah, the son of Berechiah, the son of Iddo the prophet, saying,
Darius I Hystaspis 522-486 B.C.E. seems to be the one referred to in Zechariah, Haggi, and Ezra.
Tanakh prophets date their prophecies according to the reign of a King. Zechariah dated his prophecy according to this gentile king an indication that the times of the gentiles had started.
Zechariah 1:2 The L-RD has been sore displeased with your fathers.
This actually means, “to break out in long controlled indignation”.
Zechariah 1:3 Therefore say to them, Thus says the L-RD of hosts; Turn to me, says the L-RD of hosts, and I will turn to you, says the L-RD of hosts.
“The L-rd of Hosts” (Adonai-Tzva’ot) identifies G-d’s might as commander of the hosts of Israel, heaven, etc.
This is a call to repentance. In order to fully enjoy G-d’s blessing we must repent.
Zechariah 1:4 Be ye not as your fathers, unto whom the former prophets have cried, saying, Thus says the L-RD of hosts; Turn ye now from your evil ways, and from your evil doings: but they did not hear, nor hearken unto me, says the L-RD.
Their ancestors were disobedient, obstinate, and unrepentant. Do not be like them!
Zechariah 1:5 Your fathers, where are they? and the prophets, do they live for ever?
Your fathers are dead and because of their sin, the city of Jerusalem and the temple is in ruins.
Zechariah 1:6 But my words and my statutes (laws), which I commanded my servants the prophets, did they not take hold of your fathers? and they returned and said, Like as the L-RD of hosts thought to do unto us, according to our ways, and according to our doings, so hath he dealt with us.
Returned - They repented
The exile was proof that G-d punishes those who sin and reject His warnings.