We know we learn more by constant exposure to the actions and attitudes of others than we do by words people speak. If we listen to a good preacher day in and day out but run with people who act the opposite of what the preacher is saying we are more likely to act like friends than Christlike.
Many families are a good example of this; they tell us not to be selfish with our things and then horde their bag of candy without sharing.
I know it's hard to believe but the smallest matters have the biggest impact. Small things are taken for granted as insignificant children will do what we do far more than what we say.
In fact, children can see hypocrisy and will learn to become angry that we commanded them to do things the parents are not doing. Perhaps the children will be disciplined for fighting with a neighbor child but then at the parking lot at the grocery store, they will show anger at someone who took their parking spot. I know it sounds silly but the little things are the things that count the most.
If our heart is not in control over the small things it is not likely to endure the bigger hard things.
Colossians 3:17
"And whatever you do, in word or deed, do everything in the name of the Lord Jesus, giving thanks to God the Father through him."
If you no longer have children at home you are still influencing others all the time. As believers in Christ, we are showing unbelievers what Christ looks like through our own actions and attitudes.
Romans 12:1-2
"I appeal to you therefore, brothers, by the mercies of God, to present your bodies as a living sacrifice, holy and acceptable to God, which is your spiritual worship. Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect."
