Philippians - Love Well Fruit Well

What is the key to living a spiritually healthy Christian life?
There are as many theories out there as there are people on the planet.

Paul, who wrote most of the NT, has some super insightful guidance that is both easy to understand and very practical. Paul says we need to learn to love well, and as we do this we will naturally produce spiritual fruit and replicate Jesus. BUT - how on earth do you love well?
Ka kite anoo - Craig