Today we celebrate the nativity of John the Baptist. We celebrate it on this day because we celebrate Christmas Dec 25. We count back 9 months and celebrate the annunciation on Mar 25. And since the angel told Mary that Elizabeth was her six month we count forward 3 months minus one day.
It al seems rather complex but it reminds us that the plan of God is not moment by moment, but extends across all time. How often do we get frustrated because we simply can't see how God can possibly make something good out of our present situation. We want signs. We want immediacy. When we read Romans 8 "We know that all things work for good for those who love God...." We can forget that when it says all it means all, the entire universe.
Only God can see all the moving pieces across all time and space, and therefore is the only one who knows precisely the moment when his intervention is needed in our lives for the good to result. We for our part pray, and more importantly trust.
Like John whose birth we celebrate today, each of us exists for a reason. Our lives have purpose, multiple purposes. Many we may never know in this life.
Today and every day we take what we are given, and strive one day at a time to discern God's will, and do it. The rest of it we simply have to trust God with.