Because God says so!
Write this down, for these words are trustworthy and true: To the thirsty I will give water without cost from the spring of the water of life - freely, as a gift. (Revelation
Then the Lord answered
me and said:
“Write the vision
And make it plain on tablets,
That he may run who reads it.
3 For the vision is yet for an appointed time;
But at the end it will speak, and it will not lie.
Though it tarries, wait for it;
Because it will surely come,
It will not tarry."