God promised Jacob to accompany him to Egypt and also come back with him.
“אָנֹכִי אֵרֵד עִמְּךָ מִצְרַיְמָה וְאָנֹכִי אַעַלְךָ גַם עָלֹה וְיוֹסֵף יָשִׁית יָדוֹ עַל עֵינֶיךָ.”
“”I will go down with you to Egypt, and I will also surely bring you up again; and Joseph will close your eyes.””
The Shechina came down to Egypt with Jacob with 600 thousand holy chariots.
“וַיִּסְעוּ בְנֵי יִשְׂרָאֵל מֵרַעְמְסֵס סֻכֹּתָה כְּשֵׁשׁ מֵאוֹת אֶלֶף רַגְלִי הַגְּבָרִים לְבַד מִטָּף”
“Now the sons of Israel journeyed from Rameses to Succoth, about six hundred thousand men on foot, aside from children.”
600 thousand Israelites left Egypt and the same number of Holy Chariots came out with them to protect them on the way back to the Holy Land.
Jacob passed away when he was in Egypt and brought to the Holy Land for burial. ‘I will also surely bring you up again’ is the aspect of keeping the Shechina with the children of Jacob until they were redeemed from Egypt.
“וַיְהִי, כָּל-נֶפֶשׁ יֹצְאֵי יֶרֶךְ-יַעֲקֹב–שִׁבְעִים נָפֶשׁ; וְיוֹסֵף, הָיָה בְמִצְרָיִם”
“All the persons who came from the loins of Jacob were seventy in number, but Joseph was already in Egypt.”
When Jacob and his family came first to Egypt they were 66 men + Joseph and his two sons they were 69, missings one to count as 70. Pirkei D’rabbi Eliezer (book) explains that the missing one is God that came down with them to Egypt as he promised Jacob.