I looked it up, it does look like a line from the original PS1 script. Cid says this line, in the context of Cloud being potentially short-sighted by letting people finish their personal business before entering the Northern Crater.

Cloud: No! What I meant was… What are we all fighting for? I want us all to understand that. Save the planet… for the future of the planet… Sure, that’s all fine. But really, is that really how it is? For me, this is a personal feud. I want to beat Sephiroth. And settle my past. Saving the planet just happens to be part of that. I’ve been thinking. I think we all are fighting for ourselves. For ourselves… and that someone… something… whatever it is, that’s important to us. That’s what we’re fighting for. That’s why we keep up this battle for the planet.

Barret: You’re right… It sounds cool sayin’ it’s to save the planet. But I was the one who blew up that Mako Reactor… Lookin’ back on it now, I can see that wasn’t the right way to do things. I made a lot of friends and innocent bystanders suffer… …At first, it was revenge against Shinra. For attackin’ my town. But now… Yeah. I’m fightin’ for Marlene. For Marlene… For Marlene’s future… Yeah… I guess I want to save the planet for Marlene’s sake…

Cloud: Go and see her. Make sure you’re right, and come back. All of you. Get off the ship and find out your reasons for yourselves. I want you to make sure. Then I want you to come back.

Cid: Maybe ain’t none of us’ll come back. Meteor’s gonna kill us anyway. Let’s just forget any useless struggling!

Cloud: I know why I’m fighting. I’m fighting to save the planet, and that’s that. But besides that, There’s something personal too… A very personal memory that I have. What about you all? I want all of you to find that something within yourselves. If you don’t find it, then that’s okay too. You can’t fight without a reason, right? So, I won’t hold it against you if you don’t come back.