So they sat down with him upon the ground seven days and seven nights, and none spake a word unto him: for they saw that his grief was very great. They sat down with him upon the ground seven days - They were astonished at the unprecedented change which had taken place in the circumstances of this most eminent man; they could not reconcile his present situation with any thing they had met with in the history of Divine providence. The seven days mentioned here were the period appointed for mourning. The Israelites mourned for Jacob seven days, Genesis 50:10. And the men of Jabesh mourned so long for the death of Saul, 1 Samuel 31:13; 1 Chronicles 10:12. And Ezekiel sat on the ground with the captives at Chebar, and mourned with and for them seven days. Ezekiel 3:15. The wise son of Sirach says, "Seven days do men mourn for him that is dead;" Sirach 22:12. So calamitous was the state of Job, that they considered him as a dead man: and went through the prescribed period of mourning for him.
They saw that his grief was very great - This is the reason why they did not speak to him: they believed him to be suffering for heavy crimes, and, seeing him suffer so much, they were not willing to add to his distresses by invectives or reproach. Job himself first broke silence.
Commentary on the Bible, by Adam Clarke [1831].