וַיֹּ֥אמֶר בַּרְזִלַּ֖י אֶל־הַמֶּ֑לֶךְ כַּמָּ֗ה יְמֵי֙ שְׁנֵ֣י חַיַּ֔י כִּי־אֶעֱלֶ֥ה אֶת־הַמֶּ֖לֶךְ יְרוּשָׁלִָֽם׃
And Barzillai said unto the king: ‘How many are the days of the years of my life, that I should go up with the king unto Jerusalem?
Read halakhic rulings (Jewish law) on II Samuel 19:35: and classical halakhic sources.