Parshat Vayigash

And Joseph made ready his chariot, and went up to meet Israel his father... and he fell on his neck, and wept on his neck (Genesis 46:29)

But Jacob did not embrace Joseph and did not kiss him; our sages tell us that he was reading the Shema.

(Rashi)

Why did Jacob choose that particular moment to read the Shema? Because he knew that never in his life would his love be aroused as it was at that moment of reunion with his most beloved son after twenty-two years of anguish and loss. So he chose to utilize this tremendous welling of emotion to serve His Creator, channeling it to fuel his love for G-d.

(The Chassidic Masters)