Everything that is real, which is on the level of G-d, keeps on creating.
When you say good words to someone, then those words create other good words.
If you give someone a good thought, right away he has two holy thoughts. If you do a good deed for someone, he feels like doing more good deeds. Everything continues.
G-d had so much love in His heart that He had to create the world.
You can only create with love, because G-d created the world with love.