בִּ֖י אֲדֹנָ֑י מָ֣ה אֹמַ֔ר אַ֠חֲרֵי אֲשֶׁ֨ר הָפַ֧ךְ יִשְׂרָאֵ֛ל עֹ֖רֶף לִפְנֵ֥י אֹיְבָֽיו׃
Oh, Lord, what shall I say, after that Israel hath turned their backs before their enemies!
Bereishit Rabbah
It teaches that he gave him the strength of a lion and the audacity of its cubs.