(CNN) -- Trayvon Martin's father says his heart is broken but his faith is not.
"God blessed Me & Sybrina with Tray and even in his death I know my baby proud of the FIGHT we along with all of you put up for him GOD BLESS," Tracy Martin wrote, in the first of three tweets sent about 30 minutes after the not-guilty decision was read in the Sanford, Florida, courtroom. By midnight, it had been retweeted more than 20,000 times.
Neither Tracy Martin nor Sybrina Fulton, Trayvon's mother, was in the courtroom Saturday night when a six-woman jury acquitted George Zimmerman in the death of their son, Trayvon.
An attorney for the family said he told family members it would be better if they went home so they could attend church in the morning. Attorney Darryl Parks didn't say where Martin and Fulton were spending the night but called it a "safe location."
In his tweets, Martin thanked the family's supporters and the people who will join them to "make sure that this doesn't happen again."
Martin closed by saying: "Even though I am broken hearted my faith is unshattered I WILL ALWAYS LOVE MY BABY TRAY."
Later, Fulton sent out a message that offered thanks to God, whom she said she leans on for support.
"Lord during my darkest hour I lean on you," she said. "You are all that I have. At the end of the day, GOD is still in control. Thank you all for your prayers and support. I will love you forever Trayvon!!! In the name of Jesus!!!"
Tracy Martin and Fulton were in the courtroom for most of the trial, leaving briefly when photos of their dead son were shown one time to the jury. Each of them testified during the two-week trial. They both said they believed it was their son's voice crying for help on the recording of a 911 call made the night in February 2012 when Trayvon Martin was shot and killed.
But two police investigators told the jury that Tracy Martin had said 'no' when they asked him the same question.
The 911 call was played several times, ending with the gunshot that killed Trayvon Martin. The emotional toll of that, of testifying and sitting through all the testimony and the jury selection process was difficult for the family to endure, Parks said.
Benjamin Crump, the family's lead attorney, said Trayvon Martin would have been proud of his parents.
"Your tireless work in the name of your son has made Sanford and many other cities just a little safer for all our children," he said. "I know Trayvon is up there, proud at the changes that you as his parents have inspired in his name."
When asked what he has to say to Trayvon Martin's parents, Zimmerman's brother Robert Zimmerman Jr. said, "I think it would be remiss of me not to say, I understand tonight, I understand their pain. And there are no winners. They will not win or lose anything more than they already have lost, which is their son's life, by any kind of verdict for George.
"I applaud them for asking for the verdict to be respected. ... And I will pray for them."
CNN's Allison Gilbert contributed to this story.