Please give me some tips on how to train my child to grow up holy
4 ways to steward a child in the development of holiness:
1. Set a good example, yourself. Be in a "white heat" yourself in your own love for God. Be daily in His word. Be ever running to Him with the vicissitudes of life. Nothing inspires like example. Turn off the cultural noise (media and all) until you have tended to God as your first priority, every day. No matter how disheveled the schedule, go to Him at your first discretionary moment.
2. Train your child's will. God takes a lifetime to show us as adults how exchanging our will for His will in all matters in life is actually our most fulfilled life. We were created for God, not for ourselves. We will always be slightly off the radar of the real deal, slightly out of focus, when we live for self. Therefore, believe that developing a supple will in your child is the avenue to his greatest happiness. The goal? Can he submit himself anytime, anywhere over any matter to the will of his parent, as a young child? Has the child learned to deny himself? He won't always be having to do this; normal days are filled with much give and take. But can he do it, at a moment's notice, when called upon to? A parent who is forever appeasing his child, humoring him out of his disgruntlement, bending his adult will to his child's will, trains nothing in his child. The parent already knows how to do this. It is the child who needs the practice.
3. Train your child's character. Teach him that his word is his bond. Train him in personal nobility: not to lie, to follow through with what he says, to be trustworthy. There are around 50 of these attributes. Find out what these are, and go to it.
4. Teach your child to go to (and rely upon) his own prayer closet. All of the remarkably holy saints throughout history knew the value of their own prayer closet. Each of them had discovered that this is where you recalibrate spiritually and cross-examine your motives as you hear from God through His Word and via your prayer. Daily cloistered away from the world at some moment during the day to transact business with God changes a man like the sun changes seeds in a garden. No sun, no plant, nothin', zip, zilch. Time spent in this sacred holy relationship is the core difference between raising a holy child and an academic one. This is the fastest route and the shortest distance to transformation. No man who influences the world for God does so without the prayer closet. George Mueller, Hudson Taylor, Oswald Chambers, Jim Elliot, Charles and John Wesley, Isaac Watts, François Fénelon, Andrew Murray, Charles Finney, George Whitfield, Jonathan Edwards, David Brainerd and others (read them all) of historical note lingered there often. What they conversed about in private with God alone materialized in a finished lasting spiritual work on the ground in real life.
So even if you do family devotions, then at the opposite end of the day train the child in his own devotional life, so that he learns how to rely upon God by himself for that eventful day when he grows up and leaves home. At first do his/her devotions with him/her, day after day. By virtue of your own excitement about it, make it the best part of his day. Then imperceptibly, bit by bit, remove yourself from his devotions until he is doing them without you with the same eagerness that he had when doing them with you.
Give him his own Bible (while you are still doing devotions alongside him). Start with easy versions and teach him to underline in it like a workbook (right next to you, with lots of smiles and approval) so that he can rapidly re-find his favorite verses. Also, teach him to jot down one gem from his daily devotions in a little notebook. Just one. This causes him to interact with what he reads and not just go through the motions. Teach him to pray for five minutes. That's it. You grow a spiritual muscle just like you exercise a physical one—incrementally. One chapter, one thought, one prayer. You are growing a habit. It will mushroom on its own.
If you have boys sixth grade and up, have them trade off times with the father for leading short daily family devotions, each of them standing up to read one chapter, at the foot of the dinner table, perhaps. At the close of this reading, encourage your son to make one verbal comment upon what was just read, for the edification of the family. The whole exercise will take a total of about five minutes. Done. (Long devotions turn everyone off, whether by son or father.) Men don't lead their own future families because they think it is too overwhelming of a chore, they were never in the habit of leading, and they were never trained. To not do this becomes a lifetime source of guilt and awkwardness when sons later become the heads of their own households. Require this of your sons, and appreciate them in it, and it will become the coveted joy of a man's life as God meant for it to be—fueling their manhood and assuring grand influence in the world via the piety and actions of their own family.
Training academics doesn't hold a candle to training holiness—but usually you will find that the holy saints become the most academic as well. The spiritual discipline fits them for good progress in the other. Both get done, concurrently. William Carey cataloged all the known flora and fauna in his village in India as well as serving selflessly as a missionary. Albert Schweitzer cataloged the rivers of Africa. Said again, "there is absolutely no downside to raising a holy child." The results will be the joy of your life. You can count on it.