In today's Gospel, the angel Gabriel tells Zechariah the priest about the upcoming miraculous birth of his son-to-be, John the Baptist. Zechariah is skeptical, but Gabriel says that his words "will all come true in due season."
Those words struck me. Often it can seem like God's promises are "pie in the sky." When we're stuck in the ordinariness of life, dealing with problems, God's promises seem so remote. It's easy to slip into bad habits, to forget about praying and to lose sight of the spiritual realities of life. Jesus talks about this in another Gospel passage, when he says that if the servants knew when the master of the house would return, they would stay alert. But if he delays, they start to carouse, get drunk, neglect their work...and then the owner shows up when they least expect it and they're out of their jobs!
Advent is all about waiting. So often, God seems to delay. But his words "will all come true in due season." This is even true in regard to our physical health. We can go for a long time and indulge in over-eating, or load up on greasy fries and trans-fats, while never exercising, etc. And for a while everything seems OK, and we seem healthy. But inside our bodies, the plaque is building up in our arteries and one day a stroke or heart attack will take us by surprise. But is it really so surprising? (With this I'm not trying to blame anyone for their health problems, because many things are due to genetic or other factors beyond our control. I'm just saying that some things we do can be harmful over time.)
Spiritually, it's similar. Little things add up over time. Every time we make a choice to pray, or to participate in the Mass, or go out of our way to help someone, we're building spiritual muscles. As St Paul says, "Let us not grow weary of doing good, for in due time we will reap our reward."