His tweets prompted supporters, critics and haters to pile on, adding another twist to the drama of the athlete's murder trial, which is now in recess.
Pistorius shot and killed Steenkamp last year, firing four shots through the toilet cubicle off his bathroom, saying later he thought she was an intruder. The prosecution contends he killed her in a rage after a fight.
The tweets were his first since Feb. 14, the anniversary of Steenkamp's death.
He posted the quotes Sunday and Monday, beginning with a line from the Book of Psalms, "The Lord is close to the brokenhearted."
Pistorius quoted Austrian psychiatrist and Holocaust survivor, Viktor Frankl, who believed that even in times of profound misery, life has meaning. He posted a photo of a passage from Frankl's book, "Man's Search for Meaning" – pictured with a man's finger on the page – stating that love is the highest human goal and the source of man's salvation.
Part of the Frankl passage reads, "I understood how a man who has nothing left in this world still may know bliss, be it only for a brief moment, in the contemplation of his beloved."
Pistorius also tweeted a collage of photographs of himself with disabled children and the words, "You have the ability to make a difference in someone's life. Sometimes it's the simple things you say or do that can make someone feel better or inspire them."
Monday morning he tweeted a prayer. "Lord, today I ask that you bathe those who live in pain in the river of your healing. Amen."
Some saw the tweets as a cry for help. Others weren't impressed. Some called it a cry for attention or a public relations exercise. Many bluntly replied to Pistorius that he was guilty and going to jail.
In some cases,
"I don't give a damn what #OscarPistorius is tweeting. Because, you know, #ReevaSteenkamp cannot tweet anything anymore. Ever," wrote a Twitter user with the handle @Nurse_Deanie.
A Pretoria man, @MasangoWinston, wrote that he "Liked Oscar's tweets but he must face the consequences of his actions according to SA law. GOD shall deal with the rest."
"Only you know what happened only you know the pain -- may you find some way to find peace in your heart #OscarPistorius," wrote another user, @cindelsmeyer.
The tweets come a few days after Pistorius' defense advocate, Barry Roux, rested the defense's case in the athlete's murder trial in Pretoria's High Court, a trial that has been broadcast live and has attracted massive global interest.
The case has divided South Africans, with many convinced of his guilt, and others certain of his innocence.
Throughout the trial, Pistorius has presented himself as pious, religious and remorseful. Prosecutor Gerrie Nel has portrayed him as a self-obsessed, volatile hothead who loved weapons but was irresponsible about handling them.
The prosecution and defense are now in the process of writing their final legal arguments based on thousands of pages of evidence and will present their cases to the court early next month. The court will then retire to reach its verdict. South Africa does not have a jury system. The ruling will be made by a judge and two legal assistants know as assessors.