Elijah persuaded himself that he was the only worshiper in Israel of the true and living God, but the Lord revealed to him:

“Yet I have reserved seven thousand in Israel, all whose knees have not bowed to Baal, and every mouth that has not kissed him.” 

– 1 Kings 19.18

Is this an instance of 7 occurring with some kind of significance? It touches upon something spiritual, and so that might lead us to think that this instance of 7 has some kind of symbolic meaning.

This is a tough one, because we do read in the Book of Revelation that 144,000 will be in heaven from the tribes of Israel, twelve from each of the twelve tribes, which makes us see the significance of another special number in the Bible, 12, and it seems to have special meaning there.

Or was it just coincidence that there happened to be 7,000 faithful Israelites?

Here in First Kings, it could be that God reminded the prophet that he had a perfect number of people loyal to him in Israel, multiplied by a thousand, so that the situation was much better than the prophet thought that it was.

That would show that Elijah did not have full insight into the loyal people around, and that is a lesson for us, that things may not always be as bleak as they initially appear.