A children's message or children's sermon is a part of a church service dedicated to communicating an abbreviated Christian message that is palatable to small children. It might be thought of as a mini-sermon for children.
Children's messages are common part of the liturgy in Reformed Protestant and other churches prior to the children being dismissed to go to Sunday School (or Children's church). The message may be given by the pastor or a lay leader (such as the superintendent of Christian education). For a typical message, the children are asked to gather at the chancel steps and face the pews. The pastor may have some sort of object or tactile teaching aid to focus the children's attention on the topic. The sermon typically lasts two to three minutes and may end in a brief prayer.
Children's messages are often related to the main sermon and may prepare the congregation for it.