Part of Yeshayahu 55:7 says:
וישוב אל ה וירחמהו ואל אל-הינו כי ירבה לסלוח
Loose translation - "He shall to return to Adonai and he will be merciful to him and to Eloheinu, for he is abundant to forgive."
I understand the 1st part of the excerpt as the name Adonai connotes מידת הרחמים - G-d's trait of mercy
But the end of the verse puzzles me. Why does it use Eloheinu which is a reference to G-d's מידת הדין - G-d's trait of judgement - as a means of indicating G-d's forgiveness?