Numbers 20:1-13; Ps 95 If today you hear his voice, harden not your hearts; Mt 16:13-23
Today we have two reprimands from God. In the first reading Moses is reprimanded for not being faithful in showing forth the sanctity of God before the children of Israel.
Secondly, Peter is reprimanded by Jesus in the gospel with these words, "Get behind me Satan! You are thinking not as God does, but as human beings do."
Two things to consider: sanctity and sanity.
Sanctity has to do with the will and its work is to love, to choose, to act and ultimately to love what is good.
Sanity has to do with the intellect and its work is to know, to understand, to see and to ultimately see what is there.
Sanctity is to love what is good and sanity is see what is real.
Moses did not love what was good. He chose his own emotions over God's command and act with regret and bitterness toward the people of God, forgetting that they were not privy to his experience.
Peter, on the other hand, just let reality slip by him. After he grasped reality by recognizing Jesus as the Christ son of the living God, the ground of reality itself, he refused to listen to him. In one moment he is sane and the next insane.
Sounds a lot like us. How often do we profess Jesus as the son of God and then in the next moment refuse him in our life because we don't like the circumstances or situation that is unfolding due to our profession of faith.
We have to let reality become our focal point no matter the circumstances or situation. We must pray for the grace to love what is the highest good regardless of the passion that wants to take over.