Why did Hashem appear to Yaakov at this point and bless him?
Rashi, Ramban and Targum Yonasan: He blessed him with Birkas Aveilim 1 (to comfort him on the death of his mother). 2
Malbim: "B'Chol ha'Makom Asher Azkir Es Shmi Avo Elecha u'Verachticha" (Shemos 20:21) was said about building a Mizbe'ach [connected to] the ground. Here the Berachah was that Elokus will apply to Yaakov on a fixed basis, and he and his seed will be a nation prepared for Divine supernatural Hashgachah.
Oznayim la'Torah: Interestingly, whereas on the one hand, Hashem was comforting Yaakov on the loss of his beloved mother, on the other hand, the entire Berachah centers around the children of Rachel; her death was imminent. It is as if Hashem was actually comforting him in advance on her death as well. See Oznayim la'Torah, who cites a number of examples in the Torah where Nichum Aveilim took place in advance of death.
Moshav Zekenim: It is better to go to the house of mourning [than to a party] - because Yaakov mourned over Devorah and his mother, Hashem appeared to him.
Why does the Torah add the word "Od"?
Rashbam: It hints at the fact that after leaving Luz-Beis El, Yaakov called the new location too, 'Beis El.'
Hadar Zekenim: Hashem appeared to Yaakov five times, corresponding to the five Berachos he received from Yitzchak before he left.
Ha'amek Davar: Even though Hashem spoke with Yaakov in Padan Aram and in Shechem, there was no Giluy Shechinah there. Here He revealed himself again, like at the time of the dream.
