Why does the Torah insert the Pasuk dealing with the Yasom, Almanah and Ger here?
Rashi: Having taught us Hashem's strength (in Pasuk 17), it teaches 'in the same breath', His extreme humility.
How, in spite of His supreme greatness, He lowers Himself to take the part of the weakest strata of society. In the original version of Rashi:
This lesson is repeated in Nevi'im - in Yeshayah, 66:1 & 2, and again in Kesuvim - in Tehilim, 65:5 & 6.
Why does the Pasuk mention specifically "Lechem ve'Simlah"?
Rashi: This is of basic importance, since it is precisely these two things that Ya'akov Avinu Davened for.