Both churches have diminishing memberships which initiated the joint services.
"They feel like if they can join together, it will give them both a new start and a burst of energy," he said.
Representatives from both churches will meet Thursday with a list of goals, and Mr Symons will work with them to find the best way to achieve these.
This collaboration was also timely as church-goers at St Luke's broke away and formed the Lansdowne church in 1912.
Last Sunday, the congregation gathered around a foundation stone and remembered the history and the link between the two churches.
Mr Symons will deliver a five-week series of talks, starting with a session on the spiritual practice of discernment, tomorrow at St Luke's at 7.30pm or Thursday at Lansdowne at 9.45am.