In the Biblical account, Saul disobeys God, is rejected, and replaced by David. It does not hide about Saul’s sin and God’s discipline, showing the need for the true King - Jesus Christ.
1 Samuel 15:23: For rebellion is as the sin of divination, and presumption is as iniquity and idolatry. Because you have rejected the word of the Lord, he has also rejected you from being king.”
The Quranic version says that Saul is chosen as king and leads Israel to victory over Goliath with David killing him. The Quran conflates his story with Gideon’s mentioned in Gideon’s Army. This is a clear error in the Quran.
The Quran affirms some aspects of Saul’s leadership and David’s heroism. However, it omits many key elements—such as Saul’s moral failings, the role of Samuel as both a judge and prophet, the covenant with Israel and Messianic themes.
Surah 2:247–252: Their prophet said to them, “God has appointed Saul to be your king.” They said, “How can he have authority over us, when we are more worthy of authority than he, and he was not given plenty of wealth?” He said, “God has chosen him over you, and has increased him in knowledge and stature.” God bestows His sovereignty upon whomever He wills. God is Embracing and Knowing.
And their prophet said to them, “The proof of his kingship is that the Ark will be restored to you, bringing tranquillity from your Lord, and relics left by the family of Moses and the family of Aaron. It will be carried by the angels. In that is a sign for you, if you are believers.”
When Saul set out with the troops, he said, “God will be testing you with a river. Whoever drinks from it does not belong with me. But whoever does not drink from it, does belong with me, except for whoever scoops up a little with his hand.” But they drank from it, except for a few of them. Then, when he crossed it, he and those who believed with him, they said, “We have no strength to face Goliath and his troops today.” But those who knew that they would meet God said, “How many a small group has defeated a large group by God’s will. God is with the steadfast.”
And when they confronted Goliath and his troops, they said, “Our Lord, pour down patience on us, and strengthen our foothold, and support us against the faithless people.”
And they defeated them by God’s leave, and David killed Goliath, and God gave him sovereignty and wisdom, and taught him as He willed. Were it not for God restraining the people, some by means of others, the earth would have gone to ruin. But God is gracious towards mankind.These are God’s revelations, which We recite to you in truth. You are one of the messengers.
Islam has a doctrine called “Ismah” which states that prophets are infallible in conveying God's message and are protected from major sins.
This sanitising of the lives of the prophets also goes against the Bible. The biblical narrative emphasises that God’s grace works through flawed individuals, pointing ultimately to Jesus Christ, who alone is sinless and perfect.