1 Kings 3:14 - Ellicott's Commentary On The Whole Bible

I will lengthen. — In this promise only one point, “length of days,” is conditional; and it was not fulfilled. For though Solomon’s age at the time of death is not given, yet, as his reign is given as lasting forty years, it could hardly have exceeded sixty. (Josephus, indeed, with his usual tendency to amplification, extends the reign to eighty years, and makes Solomon die in extreme old age.) The rest received an extraordinary fulfilment. The greatness of Solomon’s kingdom stands out remarkable in its sudden and unique development, the fruit of David’s long career of conquest and improvement, destined to wither at once at Solomon’s death. Then, for the first and last time, did the monarchy assume something of the character of an empire, unequalled in peaceful prosperity of wealth and power, and in splendour of civilisation.