Most likely only the representatives of the tribes went to Hebron, specifically the elders (2 Samuel 5:3).1 According to 1 Chronicles 12:23–40 there were numerous men who joined the ranks of David’s army at Hebron when he was crowned as king. This event included a great feast (1 Chronicles 12:40). The emphasis is on the fact that there is national unity and complete support for David (see further Joshua 24:1; 1 Samuel 10:20).2
1 Then all the tribes of Israel came to David at Hebron and said, “Behold, we are your bone and flesh.