For thy servant vowed a vow while I abode at Geshur in Syria, saying, If the LORD shall bring me again indeed to Jerusalem, then I will {f} serve the LORD.

(f) By offering a peace-offering, which was lawful to do in any place.2 Samuel 15:8 Parallel Commentaries

Loyal to the Core
On the other hand, look at Ittai, perfectly free to go, but in order to end the controversy once for all, and to make David know that he does not mean to leave him, he takes a solemn oath before Jehovah his God, and he doubles it by swearing by the life of David that he will never leave him; in life, in death, he will be with him. He has cast in his lot with him for better and for worse, and he means to be faithful to the end. Old Master Trapp says, "All faithful friends went on a pilgrimage years …
Charles Haddon Spurgeon—Spurgeon's Sermons Volume 26: 1880

Following Christ
"And Ittai answered the king, and said, as the Lord liveth, and as my lord the king liveth, surely in what place my lord the king shall be, whether in death or life, even there also will thy servant be."--2 Samuel 15:21. SOME men have a very remarkable power of creating and sustaining friendship in others. David was a man brimming over with affection--a man, notwithstanding all his rough soldier-life, of an exceedingly tender heart--a man, I was about to say--the word was on my tongue--a man of vast …
Charles Haddon Spurgeon—Spurgeon's Sermons Volume 62: 1916

That Whereas the City of Jerusalem had Been Five Times Taken Formerly, this was the Second Time of Its Desolation. A Brief Account of Its History.
1. And thus was Jerusalem taken, in the second year of the reign of Vespasian, on the eighth day of the month Gorpeius [Elul]. It had been taken five [34] times before, though this was the second time of its desolation; for Shishak, the king of Egypt, and after him Antiochus, and after him Pompey, and after them Sosius and Herod, took the city, but still preserved it; but before all these, the king of Babylon conquered it, and made it desolate, one thousand four hundred and sixty-eight years and …
Flavius Josephus—The Wars of the Jews or History of the Destruction of Jerusalem

King of Kings and Lord of Lords
And He hath on His vesture and on His thigh a name written, K ING OF K INGS AND L ORD OF L ORDS T he description of the administration and glory of the Redeemer's Kingdom, in defiance of all opposition, concludes the second part of Messiah Oratorio. Three different passages from the book of Revelation are selected to form a grand chorus, of which Handel's title in this verse is the close --a title which has been sometimes vainly usurped by proud worms of this earth. Eastern monarchs, in particular, …
John Newton—Messiah Vol. 2

Samuel
Alike from the literary and the historical point of view, the book[1] of Samuel stands midway between the book of Judges and the book of Kings. As we have already seen, the Deuteronomic book of Judges in all probability ran into Samuel and ended in ch. xii.; while the story of David, begun in Samuel, embraces the first two chapters of the first book of Kings. The book of Samuel is not very happily named, as much of it is devoted to Saul and the greater part to David; yet it is not altogether inappropriate, …
John Edgar McFadyen—Introduction to the Old Testament