Albert Barnes Commentary 2 Kings 24:1

"In his days Nebuchadnezzar king of Babylon came up, and Jehoiakim became his servant three years: then he turned and rebelled against him." — 2 Kings 24:1 (ASV)

In his days - That is, 605 B.C., which was the third full year of Jehoiakim’s reign according to Daniel 1:1, and the beginning of his fourth year according to Jeremiah 25:1.

Nebuchadnezzar - Or Nebuchadrezzar, which is closer to the original, Nabu-kudurri-uzur. This name, like most Babylonian names, is composed of three elements: Nebo, the well-known god (Isaiah 46:1); kudur, of uncertain meaning (perhaps “crown” or “landmark”); and uzur, which means “protects.”

Nebuchadnezzar was the son of Nabopolassar and the second monarch of the Babylonian empire. He ascended the throne in 604 B.C. and reigned for 43 years, dying in 561 B.C. He married Amuhia (or Amyitis), daughter of Cyaxares, king of the Medes, and was the most celebrated of all the Babylonian sovereigns. No other pagan king occupies as much space in Scripture.

At this time, he was not yet the reigning king but was the Crown Prince and leader of the army under his father. However, since he would have been surrounded with all the state and magnificence of a monarch, the Jews would have naturally regarded him as the actual king.

Came up - Nebuchadnezzar began his campaign by attacking and defeating Neco’s Egyptian forces at Carchemish (Jeremiah 46:2). He then pressed forward toward the south, overrunning Syria, Phoenicia, and Judea. He took Jerusalem and carried off a portion of its inhabitants as prisoners (Daniel 1:1–4). After this, he proceeded southward and had reached the borders of Egypt when he was suddenly recalled to Babylon by his father’s death.

Three years - This period was likely from 605 B.C. to 602 B.C. Jehoiakim rebelled because he knew that Nebuchadnezzar was engaged in important wars in another part of Asia.