The ideas in the classical variation of the najdorf for white

Throughout all my chess tournaments i avoided the siclian by playing 2.Nc3, and i got pretty good with this line. But now, when i am getting to 1900-2000 OTB level, which also means i will play people with higher rating like 2200, 2.Nc3 becomes quite poor and i need to start learning the theory of the open sicilian. 

I was looking at some variations for white after black plays the najdorf, and the one i liked the best is the Bd2 line. I just want to know what are exactly the ideas for white, what are the goals that he tries to achieve in the opening?

(Btw the games played in this user are not mine)

The Najdorf is refuted at club level by 6.Bg5

lol

It's true. My record against Bg5 is like 4-11-2

i don't like Bg5, too agressive for me. And please respond to the topic.

If you want to play the Opocensky I'd advise studying Karpov's games in that line, he was pretty good at it  General ideas include attacking on the kingside in a more restrained manner than in other lines against the Najdorf, usually with Nb3/Be3/O-O followed by ideas like Kh1/f4/Bf3 sometimes g4 in scheveningen lines, a4 is also a good move to restrain blacks queenside expansion while you slowly maneuver your kingside attack.