«زَائِدٍ عَلَيْهِ لِفَائِدَةٍ»
More wording than the core import requires, but for a purpose.
Such a benefit may be specification, reinforcement, prevention of misunderstanding, persuasion, warning or vivid presentation. Mere verbal increase does not establish eloquent iṭnāb.
For example, jāʾa al-rasūlu al-amīnu ('the trustworthy messenger arrived') may use the extra description to establish credibility. Without a relevant purpose, the addition could become idle; context decides.