The Targum Pseudo-Jonathan keeps the voice of the Holy One personal. "I am the God of Abraham thy father; fear not, for My Word is for thy help, and I will bless thee, and multiply thy sons for the righteousness' sake of Abraham My servant" (Genesis 26:24).
Night has fallen in Beersheba. Isaac has traveled from Gerar, through the well-digging quarrels and the renaming of his father's wells. Now, in the dark, God appears.
Merit of the fathers
Notice the final phrase. The blessing will multiply Isaac's sons "for the righteousness' sake of Abraham My servant." The rabbis called this concept zechut avot — the merit of the fathers. It is one of the load-bearing pillars of Jewish theology: that the righteousness of a generation past continues to draw down blessing for the generations that follow.
This does not mean a free ride. It means a head start. Abraham's righteousness opened a door that his descendants can walk through — but only if they walk. Pseudo-Jonathan is careful to say the blessing comes for Abraham's sake, not because Isaac has done nothing.
The phrase "fear not"
The Aramaic la tidchal — fear not — appears throughout the Tanakh whenever a holy figure is at a turning point. Abraham hears it. Moses hears it. Joshua hears it. Jeremiah hears it. Isaac, shaken by the quarrels and the famine and the journeys, hears it too.
The takeaway: the God who spoke to your father still knows your name in the dark. The covenant does not expire when the patriarch does.