In 1 Chronicles 28 and 29 David assembles all the officials in Israel. He tells them of God’s promise to have his son build the temple. He encourages them to follow God’s commandments. He commissions Solomon with the task of building the house of God. David tells Solomon to serve God with a single mind and willing heart. God had given David instructions regarding the building of the temple and he gives those instructions to those present.
David has provided for the temple from his wealth and those present are asked to give freewill offerings that go into the temple treasury. David then prays a prayer of blessing to the Lord. They make sacrifices and worship together.
Solomon takes the throne. God exalts Solomon in the sight of all Israel.
Psalm 70 is a brief impassioned prayer for help to God.
Psalm 71 is likely a continuation of Psalm 70. It affirms that God is a rock of refuge. The writer has trusted in God in the past and continues to do so. It asks that God deliver him from his enemies. It blesses the Lord for His wondrous deeds.
Psalm 71 could be the prayer of a younger David continuing to put faith in God and promising it into his old age. Our chronicles chapters prove that promise to be true.