They met while they were doing their theological study - they both have Masters in Divinity - and read a book called The Next Christendom: The Coming of Global Christianity by Philip Jenkins.
Mr Kathuri said the book spoke of vibrant Christianity in Africa, Asia, and Latin America, and he said there "must be wisdom in challenging the church to send out missionaries to the west, just like the west did raise and send out its sons and daughters to those continents that I have mentioned".
"Missionary work is no longer from the west to the rest, but from everywhere to everywhere."
The pair visited Dunedin in 2014, but "really missed home".
When they returned to Kenya they thought and prayed about whether to come back to New Zealand, and later that year received an email asking them to apply for pastor positions at Ingestre Street Bible Church (ISBC).
The process took two years, but this month the family finally touched down in Whanganui and greeted the church group that had already become their "family".
Aside from family members, the church members were the first to receive a photo of Kara when she was born.
"We kind of feel as though Kara is property of ISBC," Mr Kathuri said with a smile.
The pair were excited to grow connections between New Zealand and Kenyan churches.
Mr Kathuri said it was good to have "another connection between the Kiwis and the Kenyans", and that it was "not just about rugby now".
He said there had been a large amount of missionary work with Christians coming from the west in the '80s, and now he and his wife were "just returning the favour".
"Our primary role is to care and serve the people of Whanganui and ISBC. There's a good story that we want to present, it's called the good news."
Mrs Kinyua said they would be in Whanganui "for as long as you guys want us here".
"Part of the journey is that we have come with an open heart, an open timeline, for as long as it feels right to be here, as long as we are effective in preaching God's word," she said.
They also hoped to make an impact on Whanganui's youth.
Mrs Kinyua said as New Zealand headed into winter she was missing the weather at home. They were also missing their families, and a meal called ugali. "That's really, you know, what you call 'home food'. It's funny, it's just made of corn flour, what you call maize meal . . . you just cook it in water."
Mr Kathuri said the best part was that the meal was served with roast goat.
The couple have already been treated to pavlova and fish and chips.
Mrs Kinyua loved the Whanganui River, calling it "life-giving" and saying it was particularly clean.
