וְאָנֹכִ֨י הַיּ֥וֹם רַךְ֙ וּמָשׁ֣וּחַ מֶ֔לֶךְ וְהָאֲנָשִׁ֥ים הָאֵ֛לֶּה בְּנֵ֥י צְרוּיָ֖ה קָשִׁ֣ים מִמֶּ֑נִּי יְשַׁלֵּ֧ם יְהוָ֛ה לְעֹשֵׂ֥ה הָרָעָ֖ה כְּרָעָתֽוֹ׃ (פ)
И я в этот день слаб и просто помазан; и эти люди, сыновья Серуии, слишком суровы для меня; Господь воздаст злодею за грехи его.'
Rabbeinu Bahya
ויקראו לפניו "אברך". They called out before him Avrech!” The meaning of the word אברך is the same as הברך, “the knee.” The letters א and ה are part of the group אחה'ע letters which are interchangeable. Our sages in Bereshit Rabbah 90,3 claim that the word is a composite of the two words אב ורך, “a father-figure though young in years.” There are other examples of the word רך meaning young in years, such as Samuel II 3,39 ואנכי היום רך ומשוח מלך, “and although young in years I have today been anointed king.” Other words which are composites of two words are: פרחה, which is composed of פרי חח; the word עבטיט is a composite of עב טיט.