Rashi citing Targum Yonasan: The Emes of Yakov will be given to his sons, like You swore to him in Beis Kel. Rashi - i.e. give to us the Emes that You promised to him. Fulfill Your words "Ki Lo E'ezavcha" (Bereishis 28:15).

Radak: After the land was given to Avraham and his children; Emes is to fulfill the gift to his children, for He is the true G-d. His words for good are not retracted.

Malbim: After all the Midos ("Hashem Hashem Kel Rachum v'Chanun Erech Apayim v'Rav Chesed" - Shemos 34:6) we come to Emes and Notzer Chesed la'Alafim. Midas ha'Emes is to fulfill Your promise. Fulfill Your promise to Yakov "v'Hayah Zar'acha ka'Afar ha'Aretz u'Faratzta Yamah va'Kedmah..." (Bereishis 28:14). I.e. after the Galus, their Nefesh will stick to the earth. Hashem will rise to help, and they will expand to an inheritance without borders.

Lev Eliyahu (Shemos p.65, Hagahah citing Sefer ha'Bahir of R. Nechunya ben Hakananeh): Titen is an expression of a gift. Yakov received Midas ha'Emes for a gift, and so Avraham received Midas ha'Chesed ¹ .

Rashi citing Targum Yonasan: The Chesed of Avraham will be given to his sons, like You swore to him at Bris Bein ha'Besarim.

Rashi: Avraham's reward for Chesed - he commanded his sons to guard "Derech Hashem La'asos Tzedakah u'Mishpat" (Bereishis 18:19). It does not say v'Chesed, for the Emes of fulfilling the promise to Yakov is the payment of Avraham's Chesed.

Radak: Due to Avraham's Chesed, the land was given to him and his children after him; they are Bnei Yakov.

Malbim: The promise to Avraham is called Chesed, for there was no previous obligation due to a promise.

Rashi: He swore at the Akeidah - "Bi Nishbati Ne'um Hashem Ya'an Asher Asisa..." (Bereishis 22:16).

Radak: He swore to all three Avos.

Malbim: Even though the Shevu'ah was in ancient days, Hashem is "Notzer Chesed la'Alafim" (Shemos 34:7).