The answer is: Seven days

Job 2:13 - Seven days was the usual time of mourning. Perhaps they joined him in this period, not that they stayed in one posture for the entire seven days.

When Job's friends heard about his suffering, they rushed to his side. The way they intently sat in silence for seven days is quite significant! In ancient cultures, prolonged silence as a rite of mourning wasn't just common; it showcased deep empathy. Imagine how powerful that would be in our fast-paced world—a simple act of presence over noise.

Seven days of silence might also echo numerology in the Old Testament. The number seven frequently represents completion and divine order—think of the seven days of Creation! Here, Job’s prolonged canonical silence serves as a reciprocal tribute to life's sacred rhythms situated between טוב (tob), or goodness, and שֹׁבָב (shavav), or misfortune.

Interestingly, this unbroken silence showed the friends' initial reactions without judgement or disruption. Each day enactively validated Job’s anguish before words muddied things up. But as we all know, they rightfully broke this silence, eventually leading to a dialogue teeming with anguish but also riddled with flawed advice.

Comically, do you ever wonder if they awkwardly grabbed snacks or simply watched Job cry for that whole week? Regardless, their intention was filled with love—a reminder that sometimes 'being there' is more impactful than speaking a thousand words. And trust, Job’s full restoration in later chapters proves how powerful it is to process that pain, sharing it with others.