1)
Why did he ask Hashem to show us His Chesed?
1.
Radak: If our sins overpowered, do Chesed with the sinners, and do not pay them according to their sins.
2.
Malbim: The eternal salvation should be in our days, in this generation.
2)
Why does it say "v'Yesh'acha Titen Lanu"?
1.
Malbim: It should not be a temporary Ge'ulah via mercy, rather, via Your Chesed. A condition if Chesed is that it never ceases. Mercy and all other Midos depend on the situation or deeds of the receiver or giver. Chesed is only due to Hashem, and not due to the recipient - "uv'Chesed Olam Richamtich" (Yeshayah 54:8).
