The meaning is "Rebellion is as bad as the sin of divination, and stubbornness is as bad as worshipping false gods (iniquity), and teraphim (idolatry)."
Other Barnes' Notes entries containing 1 Samuel 15:23:
DISCLAIMER: Church of the Great God (CGG) provides these resources to aid the individual in studying the Bible. However, it is up to the individual to "prove all things, and hold fast to that which is good" (I Thessalonians 5:21). The content of these resources does not necessarily reflect the views of CGG. They are provided for information purposes only.