In I Samuel 28:16 “Samuel said, ‘Why then do you ask me, since the LORD has departed from you and has become your adversary?'”
The background to that unusual verse is that Saul had sought God in :6 of this chapter, but He would not answer him. He had disobeyed and compromised and oppressed God’s servant David for too long. There was now nothing that God was going to do for him but judge him. Saul, seeking some word about his impending fortune (as if he didn’t know!) consulted Samuel through a medium. In a very unusual instance — which does NOT commend the occult to us, by the way, as this incident only led to Saul’s defeat and death — God allowed Samuel to share this bad news: “Why then do you ask me, since the LORD has departed from you and has become your adversary?”
Basically Samuel was saying: if God is against you, why consult ME? What good is anything else going to do you when you have consistently placed yourself in opposition to Him? No scheme, no plan, no idea, NOTHING is going to help you if you are not aligned with God!
It is like the famous verse from Romans 8:31, reversed: “If God is for us, who is against us?” Yes, but the reverse is also surely true: “If God is against us, who or what can be FOR us?”!!! What ally can you summon against Him? What plan can you conceive that will prosper? Who can frustrate Him? The only sensible thing one can do is to make sure that God is not against you! Commit your life to Jesus as your Lord & Savior, repent of your rebellious ways, and follow His precepts wholeheartedly. Then you can claim the promise of Romans 8:31. But if you continue in rebellion against Him, there is no hope for you. If God is against you — then what can be for you?