He was commenting on a mobile phone message Ms Steenkamp had sent him. The athlete also denied ever shouting at her and regretted never telling Ms Steenkamp he loved her.
Mr Pistorius denies murdering his girlfriend, saying he accidentally killed her after mistaking her for an intruder.
Prosecutors, however, say the athlete intentionally killed Ms Steenkamp on February 14, 2013 by firing a gun through a bathroom door at her after a row at his Pretoria home.
A South African prosecutor accused Oscar Pistorius of blaming other people for his mistakes, as he sought to prove the Olympic and Paralympic athlete murdered his girlfriend Reeva Steenkamp.
With the trial now in its 19th day, prosecutor Gerrie Nel, whose reputation as one of South Africa’s toughest attorneys has earned him the nickname ‘The Pitbull’, has sought to portray Pistorius as an arrogant hot-head who is reckless with firearms.
He took the athlete to task over the incident of shooting at a restaurant. Pistorius had told the court that the gun was given to him by a friend under the restaurant table and went off by itself, but Police captain, Christian Mangena, gave evidence earlier in the trial, saying the weapon could only fire if the trigger was pulled.
Nel said, “We are getting into this quite a lot if we carry on, that you will blame anybody but yourself.”
The Paralympic star said that he could not explain how the gun went off and questioned his own defence advocate Barry Roux’s decision not to cross-examine Mangena on his evidence.
Gerrie Nel, said “Now, you see, Mr. Pistorius, you’re blaming everybody, you won’t take responsibility. That gun cannot fire if you don’t pull the trigger. Who pulled that trigger?”
In a dramatic opening to his cross-examination on Wednesday, Nel shocked the Pretoria court when he confronted Pistorius with a graphic photograph of the dead Steenkamp showing the side and back of her skull, her hair matted with blood and brains.
Pistorius broke down and sobbed as Nel pushed him repeatedly to take responsibility for killing Steenkamp.
The double amputee sprinter, once revered across the world for his triumph over physical adversity, faces life in prison if convicted in the Pretoria High Court of the murder of Steenkamp, a 29-year-old law graduate and model.