"First words I heard, clear as a bell - Dean Winchester is saved." Anna to Dean 4.09
The first time Dean met Cas (on earth) sparks literally flew.
Cas: "I'm the one who gripped you tight and raised you from perdition." (...)
Dean: "Who are you?"
Cas: "Castiel."
Dean: "Yeah, I figured that much, I mean what are you?"
Cas: "I'm an Angel of the Lord."
Dean: "Get the hell out of here. There's no such thing."
Cas: "This is your problem, Dean. You have no faith." Lightning flashes, and on Castiel's back great shadowy wings appear, stretching off into the distance. (...)
Dean: "Why would an angel rescue me from Hell?"
Cas: "Good things do happen, Dean."
Dean: "Not in my experience."
Cas: "What's the matter? You don't think you deserve to be saved." 4.01
Otherwise Castiel struggles with social language and interactions, but he understands Dean intimately already at their very first meeting (on earth). Cas knows jack shit about humanity and is confused the whole time, but he sees right through Dean. Cas can't understand the simple concepts humans and why they are like this, do things the way they do. But he understands exactly what Dean is thinking but can't say aloud, in a heartbeat.
"We don't know for sure, so I'm not gonna believe that this thing is a freaking Angel of the Lord because it says so! Okay. Say it's true. Say there are angels. Then what? There's a God? I don't know, guys. Proof that there's a God out there that actually gives a crap about me personally? I'm sorry, but I'm not buying it. Because why me? If there is a God out there, why would he give a crap about me? I mean, I've saved some people, okay? I figured that made up for the stealing and the ditching chicks. But why do I deserve to get saved? I'm just a regular guy." Dean to Sam and Bobby 4.02
Dean didn't believe in angels until an angel believed in him.
Cas: "I am not here to judge you, Dean. (...) You misunderstand me, Dean, I'm not like you think. I was praying that you would choose to save the town. These people, they're all my father's creations. They're works of art... Now that's not an expression, Dean, it's literal. You of all people should appreciate what that means. Can I tell you something if you promise not to tell another soul?"
Dean: "Okay."
Cas: "I'm not a... hammer as you say. I have questions, I have doubts. I don't know what is right and what is wrong anymore. But in the coming months you will have more decisions to make. I don't envy the weight that's on your shoulders, Dean. I truly don't." 4.07
"You see, sirens can read minds. They see what you want most." Sam to Dean 4.14
Sirens can switch their gender. And the siren in that episode chages from female to male for Dean, to lure him in, because what Dean wants the most is a man.
"Dean's all mine." Nick Munroe (the siren) to Sam 4.14
Dean: "Can I tell you something between you and me?"
Tessa: "Who am I gonna tell?"
Dean: "After our little, uh, experience... for that whole year, I felt like I had this... hole in my gut... like I was missing something. I didn't know what. Do you know what it was? It was you. The pain of losing my father and Sammy. I just... I wish I had gone with you for good. But I guess things are different now."
Tessa: "What? The angel on your shoulder?"
Dean: "You know about that? He just makes me feel... I don't know." 4.15
- "I'm not here to perch on your shoulder. (...) I serve Heaven, I don't serve man, and I certainly don't serve you." Cas to Dean
- "The angels? They don't care. I think maybe they just don't have the equipment to care." Dean
- "He was always a good little soldier, did anything under orders. Perfect... like a marble statue. Cold, no choice, only obedience." Anna to Dean about Castiel
Dean: "You made an exception for me."
Cas: "You're different." 4.15
"Castiel? He's not here. You see, he has this weakness. He likes you." Uriel to Dean
Cas: "Dean, you are our best hope."
Dean: "No. No way. You can't ask me to do this, Cas. Not this."
Cas: "This is too much to ask, I know. But we have to ask it."
Dean to Uriel: "I want to talk to Cas alone."
Uriel: "Really?"
Dean: "If you want snowball's chance me going in there, than you're gonna shag ass and let us talk."
Uriel: "I think I'll go seek revelation." (Uriel vanishes.)
Dean: "What's going on, Cas? Since when does Uriel put a leash on you?"
Cas: "My superiors have begun to question my sympathies. I was getting too close to the humans in my charge. You. They feel I've begun to express emotions. The doorways to doubt. This can impair my judgment."
Dean: "Well, tell Uriel, or whoever... you do not want me doing this, trust me."
Cas: "Want it, no. But I have been told we need it."
Dean: "Cas, the things that I did... what I became... You ask me to open that door and walk through it? You will not like what walks back out."
Cas: "For what it's worth, I would give anything not to have you do this." 4.16
"Why didn't you just leave me in hell? (...) I can't do it, Cas. It's too big. Alastair was right. I'm not all here. I'm not... Well, I guess I'm not the man either of our dads wanted me to be. I'm not a hero. I'm not strong enough. Find someone else. It's not me." (Dean begins to cry in front of Castiel.) 4.16
"For the first time, I feel..." Castiel 4.16
Dean: "Well, I feel stupid doing this. But... I am fresh out of options. So please. I need some help. I'm praying, okay? Come on. Please."
Cas: "Prayer is a sign of faith. This is a good thing, Dean."
Dean: "So does that mean you'll help me?"
Cas: "I'm not sure what I can do."
Dean: "Drag Sam out of here, now. Before Lilith shows up."
Cas: "It's a prophecy. I can't interfere."
Dean: "You have tested me and thrown me every which way. And I have never asked for anything. Not a damn thing. But now I'm asking. I need your help. Please."
Cas: "What you're asking, it's... not within my power to do."
Dean: "Why? 'Cause it's divine prophecy? So, what – We're just supposed to sit around and, and wait for it to happen?"
Cas: "I'm sorry."
Dean: "Screw you. You and your mission. Your God. If you don't help me now, then when the time comes and you need me... don't bother knocking." (Dean brushes past Castiel and begins to walk away, but he stops at Castiel's voice.)
Cas: "Dean... Dean!"
Dean: "What?!"
Cas: "You must understand why I can't intercede. Prophets are very special. They're protected. If anything threatens a prophet, anything at all, an archangel will appear to destroy that threat. Archangels are fierce. They're absolute. They're heaven's most terrifying weapon."
Dean: "And these archangels, they're tied to prophets? So if a prophet was in the same room as a demon –"
Cas: "Then the most fearsome wrath of heaven would rain down on that demon. Just so you understand... why I can't help."
Dean: "Thanks, Cas."
Cas: "Good luck." 4.18
"I'm dreaming, aren't I?" Dean to Castiel
Anna: "Cas got sent back home. Well, more like dragged back."
Dean: "To heaven? That's not a good thing?"
Anna: "No. That's a very bad thing. Painfully, awfully bad. He must have seriously pissed someone off."
Dean: "Cas said he had something to tell me. Something important." 4.20
Cas: "We been through much together, you and I. I just wanted to say I'm sorry it ended like this. (...) Try to understand, this is long foretold. This is your..."
Dean: "Destiny? Don't give me that 'holy' crap. Destiny, God's plan... It's all a bunch of lies! It's just a way for your bosses to keep me and you in line! You know what's real? People, families -- that's real. And you're gonna watch them all burn?"
Cas: "What is so worth saving? I see nothing but pain here. I see inside you. I see your guilt, your anger, confusion. In paradise, all is forgiven. You'll be at peace. Even with Sam."
Dean: "You can take your peace... and shove it up your lily-white ass. 'Cause I'll take the pain and the guilt. I'll even take Sam as is. This is simple, Cas! No more crap about being a good soldier. There is a right and there is a wrong here, and you know it. Look at me! You know it! You were gonna help me once, weren't you? You were gonna warn me about all this, before they dragged you back. Help me now. Please."
Cas: "I do that, we will all be hunted. We'll all be killed."
Dean: "If there is anything worth dying for, this is it." 4.22
You must be really in love to be a celestial being yet fall for the one person who doesn't believe. God told the angels to love the humans more than him. And then there was Castiel, the angel who actually did.
Pinterest folder to season 4:
https://www.pinterest.de/april31415/destiel-canon/the-beginning-s4/
video Destiel moments from season 4: