Psalms 106 goes into detail to make sure Israel knows what they did to anger God. There is no attribution of authorship,
It opens with a call to praise and the refrain found in other places: Give thanks to the Lord for he is good; for his mercy endures forever.
In vs. 2 the author issues a challenge to Israel and to us: Who can tell of his mighty acts? Who can reveal his praise?
In vs. 3 he hastens to remind us who the blessed ones are: Those who observe justice and behave with righteousness all the time.
In vs. 4 he pleads for God's blessing to come to him in the form of Salvation. He wants to be counted among the chosen and rejoice in the gladness of God's nation and glory with His inheritance.
In vs. 6. he launches into a recital of the sins of Israel beginning with the Fathers. He says they didn't understand the mercies of God. He includes the current members of Israel and prays for all of them to be blessed by God.
Even after he saved and blessed them they forgot again his mercies and goodness. They demanded better food and tested God's patience. They were envious of Moses and Aaron. He heard their demands and answered their demands but sent leanness to their souls.
The earth opened and swallowed Dathan, Abiram and his friends; fire fell from Heaven to consume the wicked ones. They preferred to worship an ox they had made to God himself. God declared He would destroy them, but Moses interceded for them and begged him to turn from his wrath. They refused to enter the Promised Land, for they doubted that He would deliver them from their enemies. They pouted and whined and he swore that he would kill them in the wilderness. They despised the pleasant land and doubted his promise.
They provoked God to anger. They defiled the land with their works sacrificing their children to pagan idols. God gave them into the hands of their enemies, but when they called to him out their affliction, he heard them and delivered them. Blessed be the Lord God of Israel. Amen. Praise the Lord.
He calls for instruments to accompany his song praising God and exalting Him.
He praises the expansive nature of God's mercy and his truth reaching to the heavens and His glory above all the earth.
In vs. 7 he quotes God and names the places that belong to God, Schechem, Succoth, Gilead, Manasseh, Ephraim, Judah, and Moab, as well as Edom and Philistia.
He ends the Psalm with praise and thanks for His help.
He claims that cursing and persecution were the clothing of his enemies and he sought God to return it to the enemies that they may suffer as they had caused others to suffer.
He sought God to reward his enemies with the evils they had laid on him.
But he pled for God to bless him and deliver him because he was week from fasting. He ends the Psalm with praise for God.
Melchizedek is refered to as Christ is other references, but it is not a widely promoted idea.