The foundation - which is based in Auckland and closely linked to the Seventh-day Adventist Church - has three houses for men and one for women, where Sarah and her baby are now living.
Residents for them are found at the church's Saturday service and community lunch, or referred by social agencies like Work and Income, the Corrections Department and Family Works.
The church gives Sarah a box of fruit and vegetables every week, and she goes to the Saturday services and has a good lunch afterward. She said the church people were very friendly, and she also attends a Bible study class once a week.
She pays for her room from her benefit, and said she was extremely grateful.
"If it hadn't been for Mr Letele's help, I don't know where we would be - Women's Refuge was full."
No alcohol or drugs are allowed at the Grace Foundation houses, though Mr Letele said that boundary had been tested. Some of the male occupants are on Te Oranganui Iwi Health Authority's alcohol and drug programme.
The foundation looks to help people who are marginalised, and have nowhere to go. Staff are mostly volunteers, who have been there themselves and know the territory.
"We share with them that change is possible. We pretty much walked that life a lot of them have come from with drugs, alcohol, violence, prison," Mr Letele said.
Volunteer teacher Terri Kara offers two-hour Bible study classes three times a week. The study is based around everyday situations and aims to help people think more clearly and make better choices.
The foundation also offers an exercise class and a communications class. It will soon have a domestic violence and parenting class, and hopes to have cooking classes later.
Mr Letele or a volunteer will visit the men's houses twice a day to make sure all is well.
The foundation works with the City Mission, Salvation Army and Koha Shed to spread donated goods like furniture around. It gets some food from Sanitarium, a Seventh-day Adventist business.
There's no government funding at all, but so much food comes to the church every Saturday that there is a "Hope Basket" for each of the houses to take away.
Asked how they manage all this, Mr Letele and Mrs Kara spoke one word, with one voice. "God," they said.
They use the resources of the church and they pray for what they need.
"It's not about us. It's about the glory of God coming through people. We are just the servants."