On November 13, the day before the 7.8 quake struck Kaikoura, Tamaki told his congregation human sin was to blame for natural disasters.
"Leviticus says that the earth convulses under the weight of certain human sin," he said in a sermon.
"It spews itself up after a while - that's natural disasters. Because nature was never created to carry the bondage of our iniquity."
Walker, his father Ross and brother Mike spoke at Destiny this morning about Ross' abuse and how God restored their relationship.
Tamaki's wife and church co-founder Hannah Tamaki joined the trio onstage.
Walker said as a child he hated his father.
"After every hiding, I used to sit there and cry and think 'God, kill him'. I used to wish he was dead."
But finding God allowed him to forgive and move on, Walker said.
"Ever since I have been saved, that's when I forgave my dad. I think when I was 18, I forgave my dad completely...this is just before I did Idol too, lucky, I might not have won."