Originally Posted by VirginiaHuguenot

Reprobate has reference to the eternal decree of God; unregenerate or unconverted has reference to the life of the soul (or rather, spiritual deadness) prior to quickening or regeneration. This distinction is worth noting.

It is the duty of unbelievers to pray to God. They sin in their prayers by doing so while lacking faith, but the sin is greater to not pray. David Clarkson ("If it be a necessary duty for unbelievers to desire these things, it is their necessary duty to pray for them" Sermon on Faith); Richard Baxter ("Prayer is a duty which God enjoined even wicked men (I could prove it by an hundred Scripture texts.)" The Right Method for a Settled Peace of Conscience and Spiritual Comfort); Jonathan Edwards ("God not only directs godly persons to pray, but others also...God is pleased sometimes to answer the prayers of unbelievers. Indeed he hears not their prayers for their goodness or acceptableness, or because of any true respect to him manifested in them, for there is none; yet he is pleased sometimes, of his sovereign mercy, to pity wicked men, and hear their cries and many others have addressed this in their works., et al." The Most High a Prayer-Hearing God); and others have addressed this.

Jacobus Koelman has a chapter on teaching children to pray in The Duties of Parents which is very useful. They should be taught that acceptable prayer is made in faith to God in the name of Christ with thanksgiving, praise and petitions according to the revealed will of God. They are to be taught not only by precept and example but to put in practice their obedience to this duty which is enjoined upon all as soon as they are able to do so.