What does the Bible say about lukewarmness?

Lukewarmness is a state of being that is neither hot nor cold in one's spiritual life, and God expresses His utter disdain for this condition in Revelation 3:15-16. It signifies a lack of zeal and true commitment to the faith, leaving one in a state of spiritual decline. The passage highlights that God would prefer if one were either fervently devoted or entirely indifferent, rather than existing in this tepid state where true passion is absent. This spiritual warmed-over condition is alarming, as it can lead Christians to grieve the Holy Spirit by not fully engaging in the spiritual growth and the grace that He bestows.