1-4 The Lord gave another message to Jeremiah. He said, “Remind the people of Judah and Jerusalem about the terms of my covenant with them. Say to them, ‘This is what the  Lord, the God of Israel, says: Cursed is anyone who does not obey the terms of my covenant!'  For I said to your ancestors when I brought them out of the iron-smelting furnace of Egypt, 'If you obey me and do whatever I command you, then you will be my people, and I will be your God.' I said this so I could keep my promise to your ancestors to give you a land flowing with milk and honey - the land you live in today.’” 5-8 Then I replied, “Amen, Lord! May it be so.” Then the Lord said, “Broadcast this message in the streets of Jerusalem. Go from town to town throughout the land and say, ‘Remember the ancient covenant, and do everything it requires. For I solemnly warned your ancestors when I brought them out of Egypt, “Obey me!” I have repeated this warning over and over to this day, but your ancestors did not listen or even pay attention. Instead, they stubbornly followed their own evil desires. And because they refused to obey, I brought upon them all the curses described in this covenant.’”

9-11 Again the Lord spoke to me and said, “I have discovered a conspiracy against me among the people of Judah and Jerusalem. They have returned to the sins of their ancestors. They have refused to listen to me and are worshiping other gods. Israel and Judah have both broken the covenant I made with their ancestors. Therefore, this is what the Lord says: I am going to bring calamity upon them, and they will not escape. Though they beg for mercy, I will not listen to their cries.  12 Then the people of Judah and Jerusalem will pray to their idols and burn incense before them. But the idols will not save them when disaster strikes!  13-14 Look now, people of Judah; you have as many gods as you have towns. You have as many altars of shame - altars for burning incense to your god Baal - as there are streets in Jerusalem. Pray no more for these people, Jeremiah. Do not weep or pray for them, for I will not listen to them when they cry out to me in distress.” 15 “What right do my beloved people have to come to my Temple, when they have done so many immoral things? Can their vows and sacrifices prevent their destruction? They actually rejoice in doing evil! 16-17 I, the Lord, once called them a thriving olive tree, beautiful to see and full of good fruit. But now I have sent the fury of their enemies to burn them with fire, leaving them charred and broken. I, the Lord of Heaven’s Armies, who planted this olive tree, have ordered it destroyed. For the people of Israel and Judah have done evil, arousing my anger by burning incense to Baal.” Jeremiah 11:1-17 New Living Translation (English Standard Version link)

Do you keep your word, especially if you gave it in the form of a promise? Promises are usually for serious matters. For example, a marriage ceremony involves solemn promises to be faithful. This was God's main complaint in this section of Jeremiah. Vs 1-4 describe how the people had rejected the covenant God had with them. Jeremiah agreed that God was right to be angry with Israel's unfaithfulness and, in vs 5-8, God tells him to bring this to the attention of all the people. What was the big way Israel had broken their promise to be faithful to God? (vs 9-14)

They had started worshiping and serving multiple gods. Verses 13-14 really bring that out. And what made their brazenness worse? (vs 15)

They thought they could mess around with other 'gods' and still expect God to hear their prayers if they came to His temple when trouble was on the way. Isn't that what many people still do with God today? They ignore Him completely – until they are in serious trouble and discover the things they'd put their hopes in can't help them. Oh how this should inspire our hearts to be people who keep their word. We should be known for faithfulness in every part of our life. That includes faithfulness to our spouse if we are married. But most of all, we must be completely faithful to Christ. We can't serve Him as well as those things that people make a god of in this world.