God has not rejected his people whom he foreknew. Do you not know what the Scripture says of Elijah, how he appeals to God against Israel?
Romans 11:2 ESV

Elijah's statements in vs 3 and 4 are from 1 Kings 19:10 and 14 in which he believes he is the only faithful, living prophet left in Israel. God responded by showing his power and, in 1 Kings 19:18, saying that he had left 7000 prophets in Israel who had not surrendered to Baal. If 7000 prophets still remained, how many ordinary faithful men and women must there have also been? Even Israel at her darkest moment held many thousands of people who persevered in faithfulness to God.