Manners were God's idea first. He gave us the Golden Rule in Matthew 7:12: Do to others what you would have them do to you. Jesus set the perfect example for us when He washed the disciples' feet in John 3:3-5. He was Christ the King, but He humbled himself to serve others.
In Deuteronomy 32:46-47, we are commanded to teach our children the do's and don'ts of proper conduct. The first and best way to do that is by being good role models. Our children will imitate us whether our actions are good or bad. As parents we should model good behavior by doing kind things for others.
Scripture also tells us "To train up a child in the way he should go, and when he is old he will not turn from it." (Proverbs 22:6) One way to interpret "in the way" is to teach a child according to his or her personality or natural bent - "Just as the twig is bent, the tree's inclined." (Alexander Pope) Some children learn best in role playing activities while others like to read and study the rules. Consider your child's learning style for a more pleasant teaching experience.
Social skills learned at home can produce fruits of the Spirit '…love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, and self-control." (Galatians 5:22) Interpersonal skills such as listening, opening doors, saying please, thank you, you're welcome, and sharing with others reveal the good manners in our heart.
Rules of etiquette are in our head. Our manners are in our heart. Together they shield us against embarrassing ourselves or others. Etiquette rules tell us what to do and what not to do; however, if we correct someone's table habits in public, we embarrass them, so the manners in our heart keep us from doing that. To keep the rules and observe the manners in our heart we can set a good example and hope others will notice.
Teaching manners to our children will build their self-confidence. Turning self-consciousness into confidence, knowing that they are made in God's image, will open doors for our children to make friends, witness, and share God's Word. I Corinthians 4:7 says, "…What do you have that you did not receive? And if you did receive it, why do you boast as though you did not?"
Psalm 39:1 "…I will watch my ways and keep my tongue from sin…." As parents we should practice saying please, thank you, I'm sorry, and excuse me. We should avoid sarcasm and saying hurtful things. When we use a quiet voice to our children we encourage similar verbal communication in them.