“Take care what you do in front of your child. It is a true proverb, ‘He who sins before a child, sins double.’ Strive rather to be a living epistle of Christ, such as your families can read, and that plainly too. Be an example of reverence for the Word of God, reverence in prayer, reverence for means of grace, reverence for the Lord’s day. Be an example in words, in temper, in diligence, in temperance, in faith, in charity, in kindness, in humility.
“Do not think your children will practice what they do not see you do. You are their model picture – and they will copy what you are. Your reasoning and your lecturing, your wise commands and your good advice – all this they may not understand, but they can understand your life!”
~ J.C. Ryle
The book "The Duties of Parents" can be found here: J.C. Ryle