A verse of scripture from 1 Chronicles shows us why Saul failed – “So Saul died for his unfaithfulness which he had committed against the Lord, because he did not keep the word of the Lord, and also because he consulted a medium for guidance.” (I Chronicles 10:13 NKJV). Firstly, he was charged with unfaithfulness. This must be referring to his foray into the priest’s office when he made a sacrifice without waiting for Samuel. The other manifestation of his unfaithfulness was when he spared the fatted calves and Agag in 1 Samuel 15. He had been commanded to wipe out every living thing, but he did otherwise. God judged that as unfaithfulness. To be faithful is to be true to our callings and assignments, even when they don’t make sense to us.
The second reason for Saul’s fall was his contact with a medium. We read in 1 Samuel 28:6 that Saul sought guidance from God, but there was no answer through any of the familiar channels of revelation. In frustration, he turned to a witch. Among the several ministries of the Holy Spirit to believers is guidance. He is to guide us into all truth. Saul was at a loss here, not knowing what to do. This confusion arose because the Lord had withdrawn the Holy Spirit from him. If we miss the ministry of the Holy Spirit, we will grope in the dark. For this reason, the Bible warns us to not grieve the Holy Spirit. The Spirit is our greatest Helper. If we miss Him we miss all.