But: the conjunction here marks the contrast between what might have been expected (that Barzillai would say yes and go along with David) and what actually happened.

The question How many years have I still to live…? (literally “How many days of years of my living…?”) is merely a way of saying “I don’t have many more years to live….” Since the purpose of the question is to make an affirmation, it may be better to translate this as a statement. The second part of the question, that I should go up with the king to Jerusalem, can also be rendered as a statement, “there is no reason for me to go with you to Jerusalem.” And this element may be placed more naturally before the rhetorical question in some languages.

Quoted with permission from Omanson, Roger L. and Ellington, John E. A Handbook on the First and Second Books of Samuel, Volume 2. (UBS Helps for Translators). New York: UBS, 2001. For this and other handbooks for translators see here .