Moses is told to speak to the rock and instead he strikes the rock. Then he takes credit for the water gushing forth. This sin has grave consequences. Moses is not allowed to lead the people into the land. Are there grave consequences for us when we are disobedient?

The snake that Moses lifted up saved the people from physical death. Jesus saves us from spiritual, eternal death.

John 3:14-15
Just as Moses lifted up the snake in the desert, so the Son of Man must be lifted up, that everyone who believes in him may have eternal life.

In Moses’ detailed journal of the exodus from Egypt he records 40 moves. Anything significant in that number?

The number forty is used by God to represent a period of testing or trial (the length of time necessary to accomplish some major part of Gods plan in his dealings with various portions of mankind). Pay close attention to the times the number 40 is used in Scripture.