Dragon Ball Z, Season 4

Kami:
Perhaps my time as guardian of Earth has come to an end.

Mister Popo:
No Kami! You are still needed! The people of Earth still need you to watch over them!

Kami:
You are too kind, Mister Popo. But I must act for the good of the Earth. This is about the continuing struggle for power between the forces of good and evil...and the danger that looms over us now poses a greater threat than anything we have faced in the past...even Vegeta with all of his strength was no match for these androids. Super Saiyan or not, he was tossed aside like a ragdoll. These androids will be difficult to beat. Even if Goku recovers from his illness, he will provide little resistance against these powerful new foes. In our combined form, Piccolo may be the only one strong enough to win this fight.

Piccolo:
We agree. The force that threatens Earth is bigger than both of us. But at least when our powers are united, we still stand a chance. And no matter how slim that chance is, we must take it.