I looked around for the meaning of those words and this is what I found בס”ד:
1. The Darchei Chaim writes that according to the R”I in Tosfos Shabbos 55A that the righteous still have Zechus Ovos it is referring to righteous people. But according to Rabbeinu Tam that Zechus Ovos is finished, it is referring that Hashem remembers that the Ovos spread Emuna in the world and they merited Hashem’s compassion as it says: ‘כי ידעתיו למען אשר יצוה’. Therefore, if we continue in their path we will also be deserving of Hashem’s compassion.
2. The Ben Ish Chai in Beshalach writes that Hashem remembers the compassion that He promised the Ovos to bestow on their descendants as it says:
‘וְשָׁמַר ה’ אֱלֹקיךָ לְךָ אֶת הַבְּרִית וְאֶת הַחֶסֶד אֲשֶׁר נִשְׁבַּע לַאֲבֹתֶיךָ’.
3. The Maase Rokeach writes that Hashem continually has in mind there should be the holy Ovos. It is a continuation of ‘וקונה הכל’, Hashem created, sustains and bestows His compassion to the world in the merit of the Ovos.
4. The Meshech Chochma in Bechokosai writes that in order for goodness to be real, it has to be everlasting, otherwise it is lost. Therefore, we say that Hashem remembers the compassion and goodness He did for the Ovos, and He’ll continue to do goodness for us and redeem us, in order it should be real goodness.