Bible Notes Online - 1-Chronicles 11 - ESV
Commentary

v1-2: David was faithful long before he became king; he had proved himself faithful in whatever he did; see 1 Tim 3.10.

v3: David was called king even before he was anointed king by the elders of Israel. They had now recognised that God had already set him apart as king. His character was the character of a king. (See 2 Sam 5.3)

v4-5: See 2 Sam 5.6-12. The capture of Jerusalem was proof of David's kingship. The Jebusites thought their city impregnable.

v6: Joab took the opportunity to attack the city; he succeeded and became chief and captain. He also became the source of many problems for David. David was well able to lead the attack, and capture the city for himself. Doubtless it would have been better if he had.

v7-9: David lived in the city. He became great and God was with him.

v10-47: See notes at 2 Sam 23. David's mighty men; different individuals, different backgrounds, different abilities; all fought with David, and gave him their support. They were faithful to him, and were prepared to give their lives for him. The Lord Jesus demands similar faithfulness from all who know and love Him.