For at that time men came to David day after day to help him, until he had a great army, like the army of God.
We have here an account of those that appeared and acted as David's friends, upon the death of Saul, to bring about the revolution. All the forces he had, while he was persecuted, was but 600 men, who served for his guards; but, when the time had come that he must begin to act offensively, Providence brought in more to his assistance.
Commenting on 1 Chronicles 12:1-22
And there they were with David three days, eating and drinking,.... Keeping a festival, to testify their joy on this occasion: for their brethren had prepared for them; not the inhabitants of Hebron only, but all the country round about, brought in provisions on this joyful occasion; otherwise the men of Hebron would not have been able to have provided what was sufficient for such...
the host of God--that is, a great and powerful army.