About parenting or about all of life?
In theory this quote is about parenting, but really this seems to apply to pretty much all of life if you swap in "It's" as I've done below:
[It's] all about living by the principle of prepared spontaneity. You don’t really know what’s going to happen next. You don’t really know when you’ll have to enforce a command, intervene in an argument, confront a wrong, hold out for a better way, remind someone of a truth, call for forgiveness, lead someone to confession, point to Jesus, restore peace, hold someone accountable, explain a wisdom principle, give a hug of love, laugh in the face of adversity, help someone complete a task, mediate an argument, stop with someone and pray, assist someone to see his heart, or talk once again about what it means to live together in a community of love.
What you do know is that Scripture gives you the wisdom that you need, and your always-present Messiah gives you the grace that you need to be ready to respond to the moments of opportunity he will give you.