In Deuteronomy 17:14-20 God wanted the appointed king to be humble and focused on the things of God. In Psalm 72 David wrote out a prayer to his son Solomon. Three times in it he stressed caring for the poor.

Deuteronomy 17:

14 “You are about to enter the land the Lord your God is giving you. When you take it over and settle there, you may think, ‘We should select a king to rule over us like the other nations around us.’ 15 If this happens, be sure to select as king the man the Lord your God chooses. You must appoint a fellow Israelite; he may not be a foreigner.

16 “The king must not build up a large stable of horses for himself or send his people to Egypt to buy horses, for the Lord has told you, ‘You must never return to Egypt.’ 17 The king must not take many wives for himself, because they will turn his heart away from the Lord. And he must not accumulate large amounts of wealth in silver and gold for himself.

18 “When he sits on the throne as king, he must copy for himself this body of instruction on a scroll in the presence of the Levitical priests. 19 He must always keep that copy with him and read it daily as long as he lives. That way he will learn to fear the Lord his God by obeying all the terms of these instructions and decrees. 20 This regular reading will prevent him from becoming proud and acting as if he is above his fellow citizens. It will also prevent him from turning away from these commands in the smallest way. And it will ensure that he and his descendants will reign for many generations in Israel.

Psalm 72:

Give your love of justice to the king, O God,
and righteousness to the king’s son.
2 Help him judge your people in the right way;
let the poor always be treated fairly.
3 May the mountains yield prosperity for all,
and may the hills be fruitful.
4 Help him to defend the poor,
to rescue the children of the needy,
and to crush their oppressors.
5 May they fear you as long as the sun shines,
as long as the moon remains in the sky.
Yes, forever!
6 May the king’s rule be refreshing like spring rain on freshly cut grass,
like the showers that water the earth.
7 May all the godly flourish during his reign.
May there be abundant prosperity until the moon is no more.
8 May he reign from sea to sea,
and from the Euphrates River[b] to the ends of the earth.
9 Desert nomads will bow before him;
his enemies will fall before him in the dust.
10 The western kings of Tarshish and other distant lands
will bring him tribute.
The eastern kings of Sheba and Seba
will bring him gifts.
11 All kings will bow before him,
and all nations will serve him.
12 He will rescue the poor when they cry to him;
he will help the oppressed, who have no one to defend them.
13 He feels pity for the weak and the needy,
and he will rescue them.
14 He will redeem them from oppression and violence,
for their lives are precious to him.
15 Long live the king!
May the gold of Sheba be given to him.
May the people always pray for him
and bless him all day long.
16 May there be abundant grain throughout the land,
flourishing even on the hilltops.
May the fruit trees flourish like the trees of Lebanon,
and may the people thrive like grass in a field.
17 May the king’s name endure forever;
may it continue as long as the sun shines.
May all nations be blessed through him
and bring him praise.
18 Praise the Lord God, the God of Israel,
who alone does such wonderful things.
19 Praise his glorious name forever!
Let the whole earth be filled with his glory.
Amen and amen!
20 (This ends the prayers of David son of Jesse.)