Because the Autobots stopped the Decepticons from stealing Earth's resources, the governments of the world have agreed to give Optimus Prime the energy he needs to revitalize Cybertron.
14 seconds sound clip from The Transformers (1984) - More Than Meets the Eye TV Series.
You can hear this line at 00:20:53 in the DVD version of the movie.
Quote context
[...]
- Can I go back to Cybertron with you?
- Maybe you'd better ask your father.
- Only if I can come with you.
- It's probably the first time all the governments ever agreed on anything.
- Well, that's it from Earth. Next stop: Cybertron.
- Ready, Spike? It's almost time to blast off.
[...]