In parashat Vayechi Yakov Avinu is about to leave this world he called Yosef.

וַיִּקְרְב֣וּ יְמֵֽי־יִשְׂרָאֵל֮ לָמוּת֒ וַיִּקְרָ֣א ׀ לִבְנ֣וֹ לְיוֹסֵ֗ף

And when the time approached for Israel to die, he summoned his son Joseph

The Zohar asks why he called only Yosef. The answer is that Yosef was more of his son than the other brothers. There was a special connection between the soul of Yakov Avinu and Yosef’s soul. The Zohar explains that when Yosef had the test with Potiphar’s wife, the verse states: 

וַיָּבֹ֥א הַבַּ֖יְתָה לַעֲשׂ֣וֹת מְלַאכְתּ֑וֹ וְאֵ֨ין אִ֜ישׁ מֵאַנְשֵׁ֥י הַבַּ֛יִת שָׁ֖ם בַּבָּֽיִת

He came into the house to do his work. None of the household being there inside. (Genesis 39:11)

The meaning of  no-one being there from the people of the house is that there was no-one from the house but there was something else. According to the Zohar there was דיוקנא דיעקב (diukana d’Yakov). The simple meaning of דיוקנא דיעקב is picture or image of the face of Yakov. When Yosef was in the middle of his test, he looked up and saw דיוקנא דיעקב which gave him strength to overcome the test. The idea of דיוקנא דיעקב is not that Yosef had a picture of his dad in his wallet. The deeper understanding is...