today's other readings are Acts 4: 32-37 and Psalm 93
As we read in John 3: 1-2, a Pharisee named Nicodemus comes to Jesus at night. This is not a coincidence. Nicodemus, does not want to be seen by his colleagues, as he knows he would be attacked if the news spread that he had come to Jesus. But he is also is in darkness as to who Jesus is.
In this passage Jesus enlightens Nicodemus by referring to the raising of the serpent in the desert by Moses in Numbers 21: 9, so too will Jesus be lifted up - onto the cross. And while the people of Moses' time were saved by looking at what he had raised, eventually they would die.
We too will die - but our saving will result in eternal life.
Praise to you, Lord Jesus Christ.