2 Samuel 17:11
Therefore I counsel that all Israel be generally gathered unto thee, from Dan even to Beer–sheba, as the sand that is by the sea for multitude; and that thou go to battle in thine own person.
Cross-references
2 Samuel 24:2 uses the same 'from Dan to Beersheba' phrase to command a census — a parallel expression for the whole nation.
2 Samuel 3:10 uses the same 'from Dan to Beer-sheba' to describe the extent of David's throne over all Israel.
Genesis 22:17 promises descendants 'as the sand that is on the seashore' — the exact simile used for the gathered army.
Joshua 11:4 describes a Canaanite horde 'like the sand on the seashore' — same simile for a vast multitude.
Judges 20:1 also says 'from Dan to Beersheba' as one man — the same phrase for gathering all Israel.
1 Kings 4:20 says Israel was 'as many as the sand by the sea' in Solomon's reign — same phrase for abundant numbers.
1 Samuel 3:20 uses the exact same phrase 'from Dan to Beer-sheba' to describe all Israel knowing Samuel was a prophet.
Psalm 3:1 laments the many enemies rising against David — the same multitude Hushai gathers in Absalom's rebellion.
Genesis 13:16 uses the 'dust of the earth' simile for countless offspring — similar to the 'sand by the sea' multitude here.