Sforno on Genesis 33:20/ספורנו על בראשית ל״ג:כ׳

1ויקרא לו א-ל אלו-הי ישראל. When he prayed he referred to G’d as the G’d Who is the אלו-הי ישראל, corresponding to his vow that והיה ה' לי לאלו-הים, “G’d the merciful will be accepted by me as the G’d of Justice.” This standard of being judged by the attribute of Justice commenced only at the time when Yaakov had qualified for this level of righteousness having been given the additional name of Yisrael.