וְעַתָּה֙ הִנֵּ֣ה יָדַ֔עְתִּי כִּ֥י מָלֹ֖ךְ תִּמְל֑וֹךְ וְקָ֙מָה֙ בְּיָ֣דְךָ֔ מַמְלֶ֖כֶת יִשְׂרָאֵֽל׃
און אַצונד, זע, איך װײס אַז קיניגן װעסטו קיניגן און אין דײַן האַנט װעט זיך אָפּשטעלן די מלוכה פֿון ישׂראל.
Rashi
I know that you will surely reign. For I see that the Holy One, Blessed is He, saves you from my hand. The Midrash Aggadah states, that Shmuel gave him this sign, that the one who tears his robe will reign after him.12See above 15:27–28.