The author of Psalm 49 is seeing the power of money used against him, through bribes and manipulation. It's a riddle to him, but he comes to the conclusion that as powerful as money is here on this earth, it cannot cross the line into eternity. Death is the great equalizer where we all stand (rich or poor, master or slave, influential or unknown) before God on level ground, and Yahweh himself is the only one who has the power to redeem us from death.
Peter’s message presents the gospel, and God opens the eyes of 3000 people to repent of their sin and turn to Jesus. Now, those 3000 are looking to live out this new identity in Christ as this gospel begins to bear fruit in their lives.
Jesus begins a conversation about wealth, and how his followers should think about possessions and riches.
What is the purpose of church? Is it that we have spotless theology? Is it that love our neighbors no matter what we believe? Or is it both?