Why is it significant that God turned Israel away from the simplicity of the Gospel?

The prophet Zechariah addressed the people of Israel, highlighting that their disobedience and complicating the Gospel resulted in God's disfavor. As stated in Zechariah 1:2, the Lord was sore displeased with the fathers of Israel for turning their backs on the simplicity of His message. When believers add burdensome requirements to the Gospel, they not only misrepresent God's grace but also lead themselves and others into a works-based mindset. The clarity of salvation found in Christ alone is vital; it must remain uncontaminated by human expectations or conditions, lest the true Gospel be obscured.