How do we know God's purpose is to save a remnant?

Scripture repeatedly affirms God's commitment to preserving a remnant of His people, as emphasized in Zechariah 13:8, where two-thirds will be cut off but a third will remain, symbolizing God's elect. This doctrine is rooted in the election of grace, affirming that God's salvific purpose is not thwarted by human rebellion or external pressures. Throughout the Bible, from the Old Testament prophets to the New Testament, we see God's faithfulness to His chosen ones even amidst persecution and trials. The assurance given in Romans 11:5 delineates that there is a remnant according to the election of grace, providing hope to believers of God's unwavering commitment to save His people.