When asked what children should be given to read, Fr. Ambrose wrote: "It is my opinion that a young mind should first of all be occupied with sacred history and readings of the Lives of saints of your choice, which will unnoticeably sow the seeds of the fear of God and Christian life. You especially need to make them understand, with God's help, how important it is to keep God's commandments and what disastrous consequences follow when we break them. All of this will lead them away from the example set by our first parents, who ate the forbidden fruit and were therefore exiled from Paradise. You can put Krylov's fables away until later, for now teaching your child some prayers by heart, like the Symbol of Faith and certain Psalms, for example: He that dwelleth in the help of the Most High (Ps. 90),The Lord is my light (Ps. 26), and the like. The main thing is that the child himself be occupied, according to his strength, and directed toward fear of God. Everything good and kind comes from this, while, to the contrary, idleness and not being instilled with the fear of God are often the cause of all evil and misfortune.
"When the fear of God is not instilled, children will not bring forth the desired fruits of good morals and a well-ordered life, no matter what you occupy them with. When the fear of God is instilled, all occupations are good and profitable."
Reference: http://www.pravoslavie.ru/english/47530.htm