I will add fifteen years to your life is literally “I have added to your days fifteen years.” In other languages it may be more natural to say “I will cause you to live fifteen years longer” or “I will give you life for another fifteen years yet.” The LORD agrees to prolong Hezekiah’s life by fifteen years, starting from the time that he would have died according to God’s original intention.

I will deliver you and this city …: The city referred to is Jerusalem, the capital in which Hezekiah lived. In some languages it may be wise to make this information explicit as Good News Translation has done, and the whole expression may be reworded to sound more natural. Some languages, for example, may prefer to say “I will not let the city of Jerusalem fall [to the Assyrian ruler] and you will therefore be saved also.”

Out of the hand of the king of Assyria may be rendered “from the power of the Assyrian king.” Bible en français courant uses figurative language that is suitable to the context here, saying “from the claws of the king of Assyria.”

I will defend this city: See the comments on 2 Kgs 19.34. The Hebrew verb used here is elsewhere translated “protect” (Isa 31.5; Zech 9.15). The same verb is used in this context by certain modern versions (New Jewish Publication Society’s Tanakh, Revised English Bible, Nouvelle version Segond révisée, Bible en français courant). New American Bible has an expression that is more picturesque, but no less accurate: “I will be a shield to this city.”

For my own sake and for my servant David’s sake: Compare 2 Kgs 19.34, where the same expression is used in Hebrew even though the Revised Standard Version wording is slightly different. Yahweh’s action in saving the city goes beyond answering Hezekiah’s prayer. It is for his own sake and in order to safeguard the dynasty of David that he acts to protect Jerusalem.

Quoted with permission from Omanson, Roger L. and Ellington, John E. A Handbook on 1-2 Kings, Volume 2. (UBS Helps for Translators). New York: UBS, 2008. For this and other handbooks for translators see here .