Sefat Emet, Genesis, Vayishlach 15:5

וחז”ל דרשו בפסוק ויקרא לו. הקב”ה קראו ליעקב אל. אתה אלוה בתחתונים. כי קריאה הוא לשון מינוי כמ”ש בגמרא ויקרא לאור יום קריא רחמנא לנהורא ופקדי’ אמצוותא דיממא כו’ כן המשכת אלקות לתחתונים הוא ע”י יעקב אע”ה. וז”ש שצורתו חקוקה והוא הסולם שעולים ויורדים בו כחות אלקות שנקראו מלאכים:

And our sages expounded the verse “and He called him”: the Holy One, blessed be He, called Jacob “El,” saying, “You are a godliness among the lower realms.” For “calling” is a term of appointment, as stated in the Talmud: “And God called the light ‘day,’ meaning that the Merciful One called the light and appointed it for the commandment of the daytime,” and so too the drawing down of divinity into the lower realms comes through Jacob, peace be upon him. And this is what is meant when it is said that his form is engraved above, and that he is the ladder through which forces of divinity – called angels – ascend and descend.

The Sefat Emet explains that when God “calls” Jacob by the name “El,” it signifies a divine appointment: Jacob becomes the channel through which holiness enters the lower world. Just as naming light “day” in the Talmud signifies assigning it a function, so too Jacob is assigned the role of drawing Godliness downward. His spiritual form above and the ladder of his vision symbolize this channeling of ascending and descending divine forces.

Summary: God’s act of “calling” Jacob is understood as appointing him to draw divinity into the lower realms, symbolized by Jacob’s engraved form and the ladder through which divine forces move.