Don’t make the mistake of choosing your own way to worship God.
You also made a reservoir for yourself between the two walls of the inner old pool. But you did not look to Him who made it from the beginning, nor did you perceive Him who created it. In that day the Lord of hosts called for weeping and mourning, for baldness and for girding with sackcloth. But instead, they celebrated in joy and gladness, slaying oxen and killing sheep, so as to eat and drink wine, saying, “Let us eat and drink, for tomorrow we die.” These things are revealed in the ears of the Lord of hosts, for this sin shall not be forgiven you until you die. (OSB)
I've been reading the Orthodox Study Bible, at least when I read the Old Testament, because it uses the Septuagint, the ancient Greek translation that was the Bible of the early church. In this case, it is very similar to our Masoretic text, but that is not always true, especially in Jeremiah, where seven entire chapters are different.
Anyway, I think the message of this text is plain. We have ideas on how to worship God. The rebuilding of Jerusalem always represents the building of the church of God, which has to be rebuilt here and there in history. Even my Catholic and Orthodox readers may agree with that, for surely the church needs revival and repentance often.
When we rebuild, though, we have to look to him who created it from the beginning. We cannot do our own thing. When God is calling for weeping, it is not the time to sing, just as when he is calling for singing, it is not the time to weep.
It is not enough to hold the Scriptures and regard yourself, or even your church, as their skilled interpreter. We must know Jesus, and the church must know Jesus.
[Jesus speaking.] “You search the Scriptures because you think that in them you have life, but these are they which testify of me, and you refuse to come to me so that you may have life. (Jn. 5:40)
I have written these things to y’all concerning those who are trying to seduce you, but the Anointing which y’all have received from him remains in you, and y’all don’t need anyone to teach you. As the Anointing teaches y’all about everything, and is true and not a lie, just as it has taught y’all, you will remain in him.(1 Jn. 2:26-27)
Sorry for how that sounds with plural yous. Every “you” in that passage is plural, and the plural yous are important. Too many people think that last passage is talking about individuals, and they regard themselves too highly, thinking they know something and not trusting what God reveals to the church, which is the pillar and the support of the truth (1 Tim. 3:15), something no individual can be.
In the church, though, we can hear God. We can look to the Creator when we rebuild, and by the Anointing we can rebuild what is true and not a lie. We can know, together, whether to fast or sing.
Let us not be deceived into thinking it does not matter, and let us be diligent followers of the One who is the living and eternal Word of God, lest we, too, be found sinning a sin which shall not be forgiven until we die.