Is hitting children with the intention of gloating or revenge, or under the influence of life's pressures, forbidden, or merely disliked to the point of tanzih (discouraged but not sinful)?

The basic principle is the prohibition of harming a child, due to the generality of the Sharia texts that forbid injustice and aggression against a Muslim, such as the Prophet's saying, peace and blessings be upon him: "Indeed, your blood, your wealth, and your honor are sacred to you," and his saying: "A Muslim is the brother of a Muslim; he neither wrongs him, nor abandons him, nor despises him." An exception to this is what contains a legally recognized benefit, such as discipline, as reported from Imam Ahmad concerning the permissibility of striking a child for discipline and for prayer when they reach the age of ten. However, striking a child without benefit, especially if it is motivated by spite, is forbidden. If the striking is for discipline but is tinged with a desire for spite, it is not forbidden, but it may be disliked because striking should not occur in a state of anger.