Why is common grace a controversial concept in Reformed theology?

Common grace is often debated within Reformed theology as it presents a tension with the notions of special grace and limited atonement. The idea that God could extend grace or favor to all of humanity is seen as undermining the effectiveness and uniqueness of His love for the elect. Proponents of 'common grace' argue that God’s kindness towards all is a reflection of His love; however, this perspective risks diluting the specific and effectual grace given to His chosen people, which is essential for salvation as emphasized in Ephesians 2:8-9. The controversy arises from the desire to maintain Scripture’s teaching on the particularity of salvation while recognizing God's sovereign will in His dealings with humanity.