Hold on here a minute. Read the whole passage and not one mere verse. In 1 Kings 19 Elijah is fearing for his life believing he was going to be killed by Jezebel and Ahab. God speaks to him and reveals things were going to change and to go back and anoint Jeru King over Israel. God comforts him with the fact that he had preserved or reserved 7,000 Israelite (and the important part) who had not bowed their knees to Baal.
In other words not everyone has been persecuted to death as Elijah was thinking and God wanted him to know that. There is no way one can force an interpretation that God set up for these people to be saved and others not and I'm taking about for eternal life salvation. These 7,000 were faithful and loyal to God as they did not bow their knew to Baal.....and God was going for his own sovereign purposed preserve these individuals from being physically killed.
It has nothing to do with God having already decided all these people would be saved spiritually speaking by some irresistible grace. There are times in God's sovereignty where he'll allow his children to become martyrs. There are other times he curtails it or stops it as in Saul before Paul....he was persecuting Christians and God stepped in and as far as Paul's measure of persecuting he was doing it was curtailed. So God wasn't going to allow all the faithful who hadn't worshiped Baal to be killed. He reserved them and protected them until the new King would take control. Not choosing for eternal life spiritual salvation! Such would be a forced interpretation without merit.
There are a myriad of problems with your understanding here.
1. Elijah has escaped, first to Judah and then to Mt. Horeb (Mt. Sinai). His life is not in danger at the point God makes His statement. He is distraught--thinking himself to be the last faithful Israelite (as opposed to Judahite). He's looking to "retire" and leave Israel to their sinfulness. It is quite the pity-party, but it is not a fear of death--which he specifically asks for.
2. God does not simply telling Elijah "this is what's going to happen;" rather God is saying "this you shall do." God is the agent of the change and His instruction to Elijah is active; it is my no means passive as you suggest. By the way, the anointing Hazael as King of Damascus demonstrates something about God's rule of all nations, not just Israel. And, God's "recommissioning" of Elijah here demonstrates to Elijah that God is not done with Israel, as Elijah had suspected.
3. Elijah is not lamenting Israelites (those in Israel as opposed to Judah) being put to death for their faith. The texts dealing with Elijah's life and ministry make it quite clear that it is not only Ahab and Jezebel who are persecuting faithful Israelites, killing them. No, quite the contrary, there were very few, if any, faithful Israelites. Notice what Elijah says: "For the people of Israel have forsaken your covenant, thrown down your altars, and killed your prophets with the sword, and I, even I only, am left, and they seek my life, to take it away.” (1 Kings 19:10 ESV). It is not the king and queen who have engaged in this persecution, it is "the people of Israel." A new king (Jehu) isn't going to fix that. In fact, Jehu is anointed to destroy the house of Ahab, which he does. He also kills all the prophets of Baal. However, he continues to worship the golden calves of Jeroboam. No King of Israel (as opposed to Judah) does what is "good" in the sight of the Lord. Israel is still hostile to those who worship Yahweh.
4. "Bowing the knee" and "Kissing" Baal are metaphors for worship. It is clear that God isn't preserving them from death, but from idolatry.
5. The phrase translated "I will leave" is the Hebrew
וְהִשְׁאַרְתִּי is a hifil stem which, in this instance, shows causation--the subject performs the action. So, God is doing something--He's causing these 7,000 to come to Him and remain faithful to Him. That's just what the Hebrew there means.
6. Paul, in Romans 11, in quoting 1 Kings 19, understands the passage as I've outlined it above. He states, rightly, that Elijah's complaint is against Israel, not her kings and queens. And he rightly translates the Hebrew as causative, relaying God's words to Elijah as "I have kept for myself..." What were they kept from? Idolatry, not death.
The Archangel