Chasidut zu Bereschit 48:15

Going back to the line: ‎את האלוקים התהלך נח‎, “Noach ‎walked with G’d;” the emphasis in this line is on the ‎attribute for G’d used, i.e. ‎אלוקים‎, the attribute of Justice. It was ‎beyond Noach’s kind of tzidkut, righteousness, to turn the ‎attribute of Justice into an attribute of Mercy through his ‎lifestyle. In this respect he was different from Avraham and ‎Yitzchok, concerning both of whom the Torah writes that they ‎‎“walked before G’d,” not merely “with G’d.” (Compare Genesis ‎‎17,1 and 48,15) In those verses the Torah wished to alert us to ‎the patriarchs’ ability to persuade G’d to substitute the attribute ‎of Mercy for the attribute of Justice, on occasion.