Exodus 3:6

And He said, I am the God of thy father, the God of Abraham, the God of Izhak, and the God of Jakob. And Mosheh covered his face; for he was afraid to look upon the height of the glory of the Shekinah of the Lord.

I AM THE G-D OF THY FATHER. In accordance with the plain meaning of Scripture, this is equivalent to saying, “the G-d of thy fathers.” However, He mentions the singular instead of the plural, for the intent is “the G-d of each one of your ancestors,” since people refer to all ancestors as fathers. Similarly: the G-d of thy father David; this is my G-d, and I will glorify Him; my father’s G-d, and I will exalt Him, meaning “the G-d of my fathers.”
Rabbi Abraham ibn Ezra said [that the word “father” in the phrase], the G-d of my father, refers to Abraham since he was the first who began to call upon the name of the Eternal. After that, He mentioned Abraham by name and then joined the rest of the patriarchs to him.. In the opinion of our Rabbis, [“father” in the phrase] The G-d of thy father, means Amram. This is just as if He had said, “I am thy G-d,” [i.e., Moses’ G-d], but He desired to associate His Name with that of a righteous man who had already died - [namely, Amram] - rather than with that of one yet alive, [i.e., Moses].” (Job 15:15). As long as a person lives, the evil inclination in him is still present. After that, [He mentioned] the G-d of Abraham, the G-d of Isaac, and the G-d of Jacob, meaning that He is the G-d of all Israel.
The reason for His mentioning “the G-d of” with each one [of the patriarchs] instead of saying “the G-d of Abraham, Isaac, and Jacob” is that He referred to His Name and His memorial, [thus alluding to the special attributes by which He was associated with each of the patriarchs], (Deuteronomy 10:17). ‘The great’ alludes to Abraham, as it is said, and of great kindness (Psalms 145:8); ‘the mighty’ to the Fear of Isaac (Genesis 31:42); and ‘the feared’ to Jacob, as it is said, For with Thee there is forgiveness, that Thou mayest be feared” (Psalms 130:4). (Ricanti in his work here on the Torah). blessed and magnified be He. I will explain yet more on this point in the chapter.