In response to how Talut (as) holds kingship over them, the Prophet (as) responded with the following points:
1) He holds kingship over you because God has chosen him over you (Spiritual Superiority).
2) He holds kingship over you because he has increased him in knowledge and physique.
3) He holds kingship over you because it's God's kingdom and he grants that to whom he pleases.
4) He holds kingship over you because God in his knowledge knows who to give authority to and is Amplegiving.
For these statements to be valid arguments, the reasons have to hold a truth basis because the Prophet (as) is not saying because he said so so it is. Rather, he is given reasons, and the reasons must be based on truth and are not due to the fact that simply it's been decided to be that way for a temporary time. Another thing to notice is the phrase Allah grants his kingdom to whom he pleases is a decription of Allah (swt). The authority belongs to God (swt) and he grants it to whom pleases. The Prophet (as) was describing a continuos reality of God (swt).
The following can be concluded from the verse:
1) The ones chosen above rest have authority over the rest.
2) Those who are most superior in knowledge and physique among God's creation hold authority over the rest.
3) The authority belongs to God (swt) so only they possess true authority, they whom he grants it to and who's authority is then linked back to God's authority.
4) God seeing of his servants, well-aware, knows who to give the authority to.
Then the sign of the kingdom is given by the Prophet (as). Remember his kingdom is God's kingdom.
And the prophet said to them: Surely the sign of His kingdom is, that there shall come to you the chest in which there is tranquillity from your Lord and remainders from what the family of Musa and the family of Haroun have left, the angels bearing it; most surely there is a sign in this if you believe
The sign of his authority thus has due to with tranquility and inheritance from the family of the two founding fathers of the nation which were Musa (as) and his brother Harun (as), two Messengers and Prophets who were sent along with each other.
The Quran then goes on to show the arguments for authority in detail and goes to prove each statement and argument. It also goes to show the significance of phrase "the family of Musa and the family of Harun", it goes on to discuss what is the tranquility, and reveals the sign of true authority which links back to God's authority through out the Quran.
So when Talut departed with the forces, he said: Surely Allah will try you with a river; whoever then drinks from it, he is not of me, and whoever does not taste of it, he is surely of me, except he who takes with his hand as much of it as fills the hand; but with the exception of a few of them they drank from it. So when he had crossed it, he and those who believed with him, they said: We have today no power against Jalut and his forces. Those who were sure that they would meet their Lord said: How often has a small party vanquished a numerous host by Allah's permission, and Allah is with the patient.
There are many points that can be derived from this verse, however, for sake of our purposes, the one thing that will be mentioned is that accepting God and the Prophet (as) of their time was not good enough to be included among the believers. The believers were the ones who were with Talut (as), not having only accepted his authority, but having been patient in his obedience which linked back to obedience to God.
So they put them to flight by Allah's permission. And Dawood slew Jalut, and Allah gave him the kingdom and wisdom, and taught him of what He pleased. And were it not for Allah's repelling some men with others, the earth would certainly be in a state of disorder; but Allah is Gracious to the creatures.
This show this part of God's grace to mankind and hence it relates to his essence. The Quran also goes on to discuss in detail the issue of oppressors and the neccessity of resisting them and also goes on to discuss the role of God's Authority with regards to that.
These are the signs of Allah: We recite them to you with truth; and most surely you are (one) of the messengers.
This verse confirms that all that has been mentioned is displaying the the truth and relates back to God and his name. What has been mentioned has eternal truth basis and is not a temprorary rule for a particular people.
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