أو تقريرها
Or reinforcing that condition.
In reinforcement, the relevant feature need not be previously unknown. Instead, the speaker seeks to impress an existing judgment more firmly upon the hearer, making its significance vivid and hard to dismiss. A concrete comparison gives established knowledge renewed force.
For instance, if the audience already knows that someone's repeated efforts achieve nothing lasting, likening those efforts to writing on water can reinforce the notion of futility. The comparison seeks consolidation and vivid impact, rather than merely revealing a previously unknown quality.