At his best
He was at the peak of his ability. He made use of all his skills.
(Modern Hebrew)
Translation
Expression (Hebrew)
הָיָה בְּמֵיטָבוֹ
Definition (Hebrew)
הָיָה בְּשִׂיא כָּשְׁרוֹ. הִשְׁתַּמֵּשׁ בִּמְלוֹא כִּשּׁוּרָיו.
(הָעִבְרִית הַחֲדָשָׁה)