Why Did God Reject Saul as King?
God rejected Saul as king because Saul disobeyed the word of the Lord, first at Gilgal (1 Samuel 13:8-14) and then in the war against Amalek (1 Samuel 15). Samuel sums it up himself: Saul rejected the word of the Lord, and the Lord rejected him as king (1 Samuel 15:23,26). This was not one slip: both times Saul put the pressure of the moment and the opinion of the people above what God had commanded.
Gilgal: the waiting Saul did not finish
Samuel had told Saul to wait seven days at Gilgal until he arrived to offer the sacrifices (1 Samuel 10:8). The Philistines were massing, the people were slipping away in fear, and the seventh day passed with no Samuel. Saul would wait no longer. He offered the burnt offering himself, and Samuel arrived just as he finished (1 Samuel 13:8-10).
Saul's defense sounds reasonable: the people were scattering, Samuel had not come, the enemy was close. He even said he felt compelled (1 Samuel 13:11-12). Samuel answered that Saul had acted foolishly and had not kept the command of the Lord. His kingdom would not last, and the Lord would seek a man after his own heart (1 Samuel 13:13-14).
What the text points to is disobedience to the command, the waiting ordered in 1 Samuel 10:8. Some readers add that Saul, not being a priest, had no right to offer the sacrifice. That may be a possible reading, but verse 13 does not state it: it speaks of not keeping the command of the Lord. Saul swapped waiting for action, and God's word for his own reading of the pressure.
Amalek: half-obedience
The second test had a clear order. God commanded Saul to carry out judgment on Amalek and spare nothing that belonged to them (1 Samuel 15:1-3). Saul won the battle but spared King Agag and the best of the sheep and cattle. What was worthless and weak, he destroyed (1 Samuel 15:8-9).
Notice what God tells Samuel: he regrets having made Saul king, because Saul has turned back from following him and has not carried out his word (1 Samuel 15:10-11). When Samuel arrives, Saul greets him with a confident line: he has fulfilled the Lord's command. The bleating of the sheep told another story (1 Samuel 15:13-14).
The excuses come in layers. First, the people were to blame. Then the animals were kept to sacrifice to the Lord (1 Samuel 15:15,21). Samuel cuts through with words that sum up the episode:
- To obey is better than sacrifice, and to listen is better than the fat of rams (1 Samuel 15:22).
- Rebellion is like the sin of divination, and arrogance is like the evil of idolatry (1 Samuel 15:23).
- Because you have rejected the word of the Lord, he has also rejected you as king (1 Samuel 15:23,26).
That last sentence answers the question in the text's own words. Saul had the altar, the livestock and the pious speech, but not what God asked for. The comparison to divination is deliberately sharp: whoever decides for himself which parts of God's word to obey has put his own will in God's place.
Saul and David: two responses to sin
Here is the point that teaches the most. David also sinned, and gravely, with Bathsheba and against Uriah. When the prophet Nathan confronted him, his answer was: I have sinned against the Lord (2 Samuel 12:13). Psalm 51 records a prayer of brokenness in which David owns the sin and asks for mercy (Psalm 51:1-4,17).
Saul also said “I have sinned” (1 Samuel 15:24). But the text shows what comes with it: he admits the error and soon explains it by fear of the people, then asks Samuel to honor him before the elders and before Israel (1 Samuel 15:24-25,30). He acknowledged the fault, yet in the same breath justified it and asked to keep his standing before everyone.
David was not spared the consequences: the sword never left his house (2 Samuel 12:10-14). Even so, the text shows him before God, confessing. The size of the sin is not what separates the two men; the difference the text lets us see is in each one's response. Scripture calls David a man after God's own heart (1 Samuel 13:14), but that verse announces the king who would come and does not give the reason. David's story suggests someone who returns to God after falling, and that is a reasonable inference, not a statement of the verse.
Did God change his mind? 1 Samuel 15:11 and 15:29
There is an apparent tension in the same chapter. In 15:11, God says he regrets making Saul king. In 15:29, Samuel says the Glory of Israel does not lie or change his mind, for he is not a man that he should change his mind. The Hebrew verb is the same, nacham (to regret, to relent, to turn back).
A frequent reading among commentators is that the two verses speak of different things. Verse 11 describes God's grief at what Saul did, a real response to a human choice. Verse 29 says God's purpose is not fickle and does not come undone by bargaining: the sentence on Saul would not be reversed by one more plea. Together they show a God who truly feels and is faithful to his word. How exactly to fit the two together is a matter where faithful believers explain things a little differently.
The end: consulting a medium
The Spirit of the Lord left Saul, and he was tormented (1 Samuel 16:14). In the end, cornered by the Philistines and getting no answer from the Lord, he consulted a medium at Endor (1 Samuel 28:6-7). The Chronicler sums up his life this way: he died because of his unfaithfulness, because he did not keep the word of the Lord and even sought guidance from a medium instead of seeking the Lord (1 Chronicles 10:13-14).
What this changes in your life
First, be wary of selective obedience. Doing the part that suits you and calling the rest “prudence” is Saul's road. Second, when God points out a failure, notice the difference between explaining and confessing. An explanation protects you. A confession puts you in God's hands.
Third, none of this is an argument for living in fear. David's story shows that whoever returns to the Lord finds forgiveness (1 John 1:9). The text of Samuel records that Saul justified his own error and sought to keep his honor before the people, and that is the attitude to avoid.
Key Bible references
1 Samuel 13:8-14 · 1 Samuel 15:22-23 · 1 Samuel 16:14 · 1 Chronicles 10:13-14 · 2 Samuel 12:13 · Psalm 51:1-4 · 1 Samuel 28:6-7