"For God did not call us to be impure, but to live a holy life" 1 Thessalonians 4:7
In order to understand what a holy life is perhaps it helps to think of what an unholy life is like. It is drought. It is helplessness in the lightest wind. It is a continuous dropping of leaves until we are left bare. It is the inability to nourish others. It is keeling over by your own weight and tearing your roots.
"They are clouds without rain, blown along by the wind; autumn trees, without fruit and uprooted - twice dead." Jude 12b
The autumn tree without fruit - the inability to nourish others - is its own sort of death. So then life is the fruit that is produced within us that others receive. We take what God has provided. Soil, water, sunlight. And from the simple and altogether complex nutrients that God gives us, we bear something ever sweeter to share with others.
Holy life is accepting the rains - tropical, spring, summer, torrential, light - that God offers and opening our roots to receive. It is to remain upright against the breeze. To fill out our branches. To offer joy in the fruit that we produce. To be a place to sit and think under.