Below are a selection of quotes from Final Fantasy VII that relate to Jenova or the Jenova project. They are sorted roughly in order by the name of the character that said them.

Jenova
    "...beacause you are a puppet."  *

Sephiroth
    "...trust me."
    "A man once told me never to use an unscientific term such as mysterious power! It shouldn't even be called magic! I still remember how angry he was."
    "Hojo of Shinra, Inc. ... An inexperienced man assigned to take over the work of a great scientist. He was a walking mass of complexes."
    "...I've always felt since I was small...That I was different from the others. Special, in some way. But... not like this..."
    "Professor Gast... Why didn't you tell me anything? ...Why did you die?"
    "Out of my way. I'm going to see my mother."
    "Ha, ha, ha... my sadness? What do I have to be sad about? I am the chosen one. I have been chosen to be the leader of this Planet. I have orders to take this planet back from you stupid people for the Cetra. What am I supposed to be sad about?"
    "I am becoming one with the planet."
    "You stupid fools. You have never even thought about it. All the spirit energy of this Planet. All its wisdom... knowledge...I will meld with it all. I will become one with it... It will become one with me."
    "...that which adds to the knowledge of... I am becoming one with the Planet. Mother... it's almost time... Soon... we will become one."
    "Only death awaits you all. But do not fear... for it is through death that a new spirit energy is born. Soon, you will live again as a part of me."
    "I'm far superior to the Ancients. I became a traveler of the Lifestream and gained the knowledge and wisdom of the Ancients. I also gained the knowledge and wisdom of those after the extinction of the Ancients. And soon, I will create the future."
    "Do not worry. Soon the girl will become part of the Planet's energy. All that is left is to go North. The 'Promised Land' waits for me over the snowy fields. There I will become a new being by uniting with the planet. As will this girl..."
    "What are you saying? Are you trying to tell me you have feelings too?"
    "Ha, ha, ha...... Stop acting as if you were sad. There's no need to act as though you're angry either. Because, Cloud. You are..."
    "What I have shown you is reality. What you remember, that is the illusion."

Cloud
    "I'll go anywhere Sephiroth is at! To beat him and put an end to all this!"
    "Terrible...Sephiroth... This is too terrible."
    "What about MY sadness!? My family... friends... The sadness of having my hometown taken away from me!? It's the same as your sadness!"
    "Sephiroth.... I trusted you...No, you're not the Sephiroth I used to know!"
    "I challenged Sephiroth and lived. Why didn't he kill me?"
    "...Shut up. The cycle of nature and your stupid plan don't mean a thing. Aeris is gone. Aeris will no longer talk, no longer laugh, cry...... or get angry......What about us...... what are WE supposed to do? What about my pain? My fingers are tingling. My mouth is dry. My eyes are burning!"
    "This is where the Reunion is happening. Where everything begins and ends."
    "He's the only one that could do it....Sephiroth. Where are you?"

Hojo
    "There's so many frivolous things in this world."
    "That's right. I recommend you think things through before you make any rash moves."
    "Haven't you ever had the feeling something is calling you? Or that you had to visit some place?"
    "I see...... This could be interesting."
    "Ha, ha, ha...... One or two Midgars? ...It's a small price to pay."
    "Show me...... Sephiroth. It should be near...Ha, ha, ha...... Go beyond the powers of science...Before your presence, science is powerless...I hate it, but I'll concede to it. Just... let me see it. Ha, ha, ha......"
    "Heh, heh, heh......... I'm even beginning to hate myself."

Bugenhagen
    "When it's time for this planet to die, you'll understand that you know absolutely nothing."
    "No matter what happens, isn't it important to try?"

* note: the spelling mistake in "because" is intentional, since it appears like that in some versions the game. Typical, isn't it? Jenova gets ONE line in the entire game, and they spell it wrong. Tsk.