The book of Zechariah starts with an appeal by God at around 500BC for the people of Israel to return to him. For many years God had persisted with those people even though they often failed to obey him. But still, God continued with them, punishing them for their evil and calling them to return to him. Without ever lowering His own expectations, he continually reached out to them and reiterated that they would eventually obey him and be blessed.
Around 1500 years earlier God had made promises to Abraham, that his descendents, who became known as Israel, would be special and blessed by God. To enjoy that blessing they had to serve God and obey his commandments.
Despite the great privilege they had though, they still couldn't find the strength to obey. The start of the book of Zechariah tells of just one of many such incidents when he was told to say,
Zechariah 1:2: "Yahweh was very displeased with your fathers. 3 Therefore tell them: Thus says Yahweh of Hosts: `Return to me,' says Yahweh of Hosts, `and I will return to you,' says Yahweh of Hosts. 4 Don't you be like your fathers, to whom the former prophets proclaimed, saying: Thus says Yahweh of hosts, `Return now from your evil ways, and from your evil doings;' but they did not hear, nor listen to me, says Yahweh. WEB
God was again calling people to obey, even though in the past such calls had fallen on deaf ears. It shows the natural rebellion of humans, and how we can't see the truly good things for the sake of all the distractions that promise pleasure or success in the short term.
But yet, God knows that weakness, and he stated that he would bear with the people of Israel and eventually they would turn to him so that he could fulfil his promise,
Zechariah 2:4: .. "Run, speak to this young man, saying, `Jerusalem will be inhabited as villages without walls, because of the multitude of men and cattle in it. 5 For I,' says Yahweh, `will be to her a wall of fire around it, and I will be the glory in the midst of her. WEB
Zechariah 2:12: Yahweh will inherit Judah as his portion in the holy land, and will again choose Jerusalem. WEB
To us, it gives both warning and a hope. The warning is that it is all too easy to ignore God, and just follow the conventions of whatever society we are in. We know from the track record of the people of Israel how easy it is to avoid listening to his message and instead flock to another message that is more palatable.
The hope is that while God won't accept us on our terms, He is patient and forgiving, and offers us all the help we need if we choose to accept it.
Jude 1:18: .. "In the last time there will be mockers, walking after their own ungodly lusts." 19 These are they who cause divisions, and are sensual, not having the Spirit. 20 But you, beloved, keep building up yourselves on your most holy faith, praying in the Holy Spirit. 21 Keep yourselves in the love of God, looking for the mercy of our Lord Jesus Christ to eternal life. WEB
Jude emphasises how it is an active process of seeking to understand God, remembering the great promises he has offered, and obeying him. The process of building up is forever an ongoing and conscious one, in order to avoid being lost among the mockers.