The truth is that God is really the best parent who ever was. He lovingly rescued His people from slavery in Egypt. He split the Red Sea to help his children to cross over safely and destroyed their enemies behind them. He caused a cloud to cover them from the heat of the day and a fire to light the way for them to see at night. He fed them manna and gave them water in the desert. After everything God did for His people in the wilderness, what was their reaction? They repeatedly turned their back on Him. If God was the best parent who ever was and couldn't control the sinfulness of His own children, does that give you hope or discouragement today? It gives me hope, and it helps me to know that I am not alone.
I can lead a horse to water, but I cannot make it drink even if I know it is thirsty. I can sit a child on the potty, but I can't make him go pee or poop even if I know it would give him relief. I can train my children in the way they should go, but I can't make them accept the Lord as their Savior unless He alone does a work in their heart.
Adam and Eve were the first parents. Let's assume that they parented each one of their kids the same way. They learned first hand from the Master in the Garden of Eden. One of their kids, Able, chose what was good, and the other, Cain, killed Able for it. Hear me when I say that the parenting was the same for both of the children, but the outcome was different.
Let us assume, as well, that the father of the prodigal son parented both of his sons the same. However, one of his sons chose what was good, and the other chose to waste his inheritance on debauchery and excess. What is the difference?
James 1:14-15 (ESV) says, "But each person is tempted when he is lured and enticed by his own desire. Then desire when it has conceived gives birth to sin, and sin when it is fully grown brings forth death."
I used to be in the parental determinism camp. I used to think that if you train up a child in the way he should go that you will get a child who knows the Lord and who is walking with Him as your finished product. I now know that is false. The old testament alone is filled with biblical examples which refute this wisdom. It is wise, but it is not a promise of God. Geneology after genealogy in the old testament talk about kings who did right in the eyes of the Lord only to have sons who succeeded them who did wrong in the eyes of the Lord.
We as parents are called to teach our children in the discipline and instruction of the Lord (Eph 6:4). We are to teach them as we walk along the way (Deut 11:19). The truth is that we cannot save them. That is God's job alone. If we are witnessing to someone about Christ, we are being obedient to what we are called to do, but we cannot make them accept Christ. Again, that is God's job.
Feel hope today. It is your job is to teach, discipline and instruct your child. It is God's job to save. Trust Him.
Here are some links to books which might be an encouragement to you in this area.