There are many ways to say or describe a reality.
We can use examples, imagery or figurative speech.
Whichever way it is, the meaning should be clear enough to be understood.
In the gospel, Jesus used an image to describe punishment for sin.
He said that if anyone who is an obstacle to bring down one of these little ones who have faith, it would be better that a millstone tied round his neck and thrown into the sea.
The meaning is clear in that the punishment is very severe.
The message is also clear enough for us not to take sin too lightly.
As the 1st reading says, let us not assume that God is compassionate and that He will always forgive.
The reading warns us that with God are both mercy and wrath, and that His rage bears heavy on sinners.
So, the 1st reading urges us not to delay our return to the Lord, or to put it off day after day.
Jesus is calling out to us to turn away from sin and to live a life that is pleasing to God.
The reward is peace in our hearts, and that is what we really want and that is also what we really need.