ANSWER: The New Testament Bible verse regarding child abuse that quickly comes to mind is in Colossians 3. The same admonition is repeated in Paul's book of Ephesians, chapter 6 and verse four. Paul states in Colossians 3 regard how a child should be treated, "Parents, do not irritate your children, or they will become discouraged." (Colossians 3:21).
Both of these are addressed to the fathers in the household and, by extension, to anyone in authority over that child. Those in authority are commanded, not suggested, to not provoke (abuse) them until he or she becomes violently angry or in a rage of frustration. To act in such a way toward a child would be against the will of God.
If a child is provoked, even for his own good (as some would argue), this is permitted but that is not what God demands. So I would have to say from these two scriptures that people in authority should not abuse these blessings from God for any reason.
Another place that might be of help to understand our Father's loving mind toward our offspring and how to treat them is the admonition to not even put barriers before "little ones" (see Matthew 18:1 - 6 and Mark 9). Clearly, Jesus takes the abuse or hindering of children, especially those who are spiritually quite young, very seriously!
As parents we must always teach in love and discipline with justice without any abuse. This does not mean an adult should be passive and not correct a child for bad and unacceptable behavior because that too is a sign of being unloving and abusive. Even God, because of his perfect love, chastens or corrects those who have his spirit as his dear child (Hebrews 12:7, Revelation 3:19).
One of the primary problems for each generation is to figure out what IS abuse. In the modern English dictionaries the definition is to attack verbally, to misuse or mistreat someone. This can be manifested in verbal insults, physical battery (although spanking done in love and for the good of the child is permitted), emotional and psychological mistreatment because of lies and hypocrisy, and spiritual deception.
Abuse, whether it be towards a child or an adult, also includes neglecting very important parts of being a human being such as withholding items of survival like food, water, and heat. Love and nurturing are vital parts is aiding humans to grow up properly.
The first lesson of mankind outside of Eden, found in the story of Cain and Abel, is that we are not to take advantage of each other. The Bible is full of stories of abuse by humans. God certainly does not like this behavior and would never approve of abuse toward a child for any reason. He is a Being of law and order. He is Love and Truth and Mercy.
In conclusion, the Bible clearly states that we should NEVER condone or be a part of child abuse or any other kind of abuse against our fellow men and women, regardless of their age. Such attitudes and actions come from the "works of the flesh," our human nature apart from God, which Paul enumerates in Galatians (Galatians 5:14 - 15, 19 - 21).I hope this brief explanation about what the Bible says about child abuse spurs you on to further study this topic in scripture.