Al-jawab billahi at-taufeeq (the answer with Allah’s guidance)
Below is an extract from ‘stories of the Prophets’ by Ibn Katheer, which will answer your question.
Prophet Shammil (Samuel)
The State of the Israelites After Joshua
Ibn Jarir reported that the condition of the Israelites deteriorated. They committed many sins and killed whom they wished of the prophets. Consequently Allah sent them tyrannous king who ill-treated them and spilled their blood, and set their enemies from outside against them as well. They used to go war, taking with them The Ark of the Covenant. They did this so that they would be victorious by its blessings, and it became a symbol of calm and a relic left behind by Moses’s people. When they went to war with the people of Gaza and Askalon, they were defeated because the Ark of the Covenant was captured from them. When the king of the Israelites heard of this he died on the spot.
The children of Israel remained like sheep without a shepherd until Almighty Allah sent them a prophet named Samuel (Shammil) (pbuh). They asked him to appoint a king over them to lead in a war against their enemies.
The Ark of the Covenant
According to Ibn ‘Asaker, the Israelites believed their Ark of the Covenant to be very holy and an important symbol of their history. The carried the Ark even in battle and believed that, because of it, Allah would protect them from their enemies. This belief gave them peace of mind and great courage, and their enemies were terrified by it. Their enemies also believed that it was given special power by Allah. Gradually the Israelites started to ignore Allah’s law; evil habits became part of their lives. Allah sent upon them an enemy, the Philistines, who defeated the Israelites, captured their Ark, drove them out of their homes, and took away their children to use or sell as slaves. Their power was broken. They separated from one another and were very disheartened.
Samuel Comes to the Israelites
Then came Prophet Samuel (pbuh) among them to bring some relief. They asked the prophet’s help in appointing a strong leader, a king under whose banner they could unite and fight the Philistines. Prophet Samuel (pbuh), knowing their weakness, told them: “I fear that when the time comes to fight you may refuse.” But they assured him that they had suffered enough insults and were now ready to fight in the way of Allah, even if they lost their lives.
Prophet Samuel prayed to Allah for guidance. Allah revealed to him that He had chosen one, Saul (Talut), to be their king. The prophet wanted to know how to recognize the future king. He was told that Saul would come to him by himself and that they should then hand over the control of kingdom to him, for he would lead them in battle against the Philistines.
Saul is Appointed King
Saul was tall and sturdy, pious, and very intelligent. He lived and worked with his father on their farm. One day, several of their donkeys were lost. Accompanied by his servant, Saul went in search of them. They traveled for many days and were very tired. Saul said to his servant: “Let us rather go back, for I am sure that my father will be worried by now, and the other animals must also be cared for.” His servant suggested that as they were already in the land of Samuel the prophet, they should go to him to inquire about the lost donkeys.
Saul agreed, and they carried on. On their way, they asked directions from some maidens carrying water. They were told to go in the direction of the mountain. Here, a vast crowd was waiting for the Prophet Samuel. When Saul set eyes on him, he instantly recognized him as a prophet by his holy men. Samuel also recognized Saul as the king that Allah had chosen for them. Saul greeted the prophet respectfully. When he asked about his missing donkeys, Samuel told him not to worry, his donkeys were already on their way to his fat’s farm. He then told Saul that Allah had chosen him as the king of the children of Israel. His duty would be to take charge of their affairs, to unite them under one banner, and to protect them from their enemies. If he carried out Allah’s commands, he would be given victory. Saul was surprised by this sudden honor offered to him. It was also a heavy responsibility. He protested to the prophet that he was a of the children of Benjamin, the least famous of the tribes of Jacob; he did not know anything of leadership or kingship and had no wealth. Samuel told him that it was the will of Allah that he should be the king, that he should thank Allah for His favor and be strong in faith.
Saul is Appointed King – Quranic
Taking Saul by the hand, Samuel led him to the children of Israel, but they insisted on a direct sign from Allah. Prophet Samuel told them to go outside the city to see the sign, which they did. Almighty Allah revealed:
“Have you not thought about the group of children of Israel after (the time of ) Moses? When they said to a Prophet of theirs: “Appoint for us a king and we will fight in Allah’s Way.” He said: “Would you then refrain from fighting, if fighting was prescribed for you?”
They said: “Why should we not fight in Allah’s Way while we have been driven out of our homes and our children (families have been taken as captives)?”
But when fighting was ordered for them, they turned away, all except a few of them. And Allah is All-Aware of the Zalimeen (polytheists, and wrongdoers).
And their Prophet (Samuel) said to them: “Indeed Allah has appointed Saul as a king over you.”
They said: “How can he be a king over us when we are better fitted than him for the kingdom, and he has not been given enough wealth.”
He said: “Verily, Allah has chosen him above you and has increased him abundantly in
knowledge and stature. And Allah grants His Kingdom to whom He wills. And Allah is All-Sufficient for His creatures’ needs, All-Knower.” And their Prophet (Samuel) said to them:
“Have you not thought about the group of the Children of Israel after (the time of) MusÂ
(Moses)? When they said to a Prophet of theirs, “Appoint for us a king and we will fight in
AllÂh’s Way.” He said, “Would you then refrain from fighting, if fighting was prescribed for
you?” They said, “Why should we not fight in AllÂh’s Way while we have been driven out of our homes and our children (families have been taken as captives)?” But when fighting was ordered for them, they turned away, all except a few of them. And AllÂh is All-Aware of the ZÂlimÛn (polytheists and wrong-doers).
And their Prophet (Samuel) said to them, “Indeed AllÂh has appointed TalÛt (Saul) as a king over you.” They said, “How can he be a king over us when we are better fitted than him for the kingdom, and he has not been given enough wealth.” He said: “Verily, AllÂh has chosen him above you and has increased him abundantly in knowledge and stature. And AllÂh grants His Kingdom to whom He wills. And AllÂh is All-Sufficient for His creatures’ needs, All-Knower.” And their Prophet (Samuel) said to them: Verily! The sign of His Kingdom is that there shall come to you At-TÂbÛt (a wooden box), wherein is Sakinah (peace and reassurance) from your Lord and a remnant of that which MusÂ (Moses) and HÂrÛn (Aaron) left behind, carried by the angels. Verily, in this is a sign for you if you are indeed believers.” (Ch. 2: 246-250)
Saul Leads an Army – Quranic
Then when Saul set out with the army, he said:”Verily! Allah will try you by a river. So whoever drinks thereof, he is not of me, and whoever tastes it not, he is of me, except him who takes thereof in the hollow of his hand.”
Yet, they drank thereof, all, except a few of them. So when he had crossed it (the river), he and those who believed with him, they said: “We have no power on this day against Goliath and his hosts.”
But those who knew with certainty that they were to meet their Lord, said: “How often a small group overcame a mighty host by Allah’s Leave?” And Allah is with the patient.
And when they advanced to meet Goliath and his forces, they invoked:
“Then when TalÛt (Saul) set out with the army, he said: “Verily! AllÂh will try you by a river. So
whoever drinks thereof, he is not of me, and whoever tastes it not, he is of me, except him who takes (thereof) in the hollow of his hand.” Yet, they drank thereof, all, except a few of them. So when he had crossed it (the river), he and those who believed with him, they said: “We have no power this day against JalÛt (Goliath) and his hosts.” But those who knew with certainty that they were to meet their Lord, said: “How often a small group overcame a mighty host by AllÂh’s Leave?” And AllÂh is with As-SÂbirin (the patient ones, etc.).
And when they advanced to meet Jalut (Goliath) and his forces, they invoked: “Our Lord! Pour forth on us patience and make us victorious over the disbelieving people.”
Saul Leads an Army
Saul set about organizing his army with strong faith and wisdom. He ordered that only men free from responsibilities should join. Those engaged in building homes, men who were about to be married and those occupied with business should not join.
After establishing a well-trained army, he decided to put them to the test. He told them that along the route they would pass a river where they should drink enough water to quench their thirst but not more than that. To his disappointment, he discovered the majority of them drank more water than they should have. He discharged them for disobedience and kept only the few who had obeyed him, as they were the ones who proved their sincerity. This resulted in a split in the army, but he was not bothered. He believed in quality and not numbers; better a small band of true believers he could rely on than a huge army of unreliable men.
Saul’s Army Sees the Enemy
Saul’s men sighted the enemy on the other side of the river. Their opponents appeared physically strong and were armed with better weapons. They were led by the mighty warrior Goliath (Galut), known for his huge build and brute strength. A great number of Saul’s men ran away on seeing this strong force. The small band that remained was willing to fight, whatever the outcome, for they had heard that there had been many incidents in the past in which Allah had caused a small force to defeat a larger one.
And Only Allah Ta’ala Knows Best.
Moulana Qamruz Zaman