What does the Bible say about man's religious efforts?

In Zechariah chapter 7, the Lord confronted the people of Israel about their fasting and mourning, which had become mere religious ceremonies devoid of true repentance and love for God. They fasted not for God but for themselves, demonstrating that their outward expressions of faith did not reflect a genuine heart for God. This illustrates a critical principle in sovereign grace theology: that no amount of religious effort can reconcile us with God. The true requirement is a heart that loves God and seeks Him in faith and repentance, as expressed through faith in Jesus Christ alone.