Why does it say "u'Kera'eni b'Yom Tzarah"?
Radak: If your Korbanos will be like this, I will save you from affliction when you call to Me, so that you will honor Me, i.e. do My Mitzvos. However, one who offers Korbanos and does not repent from his evil, he disgraces Hashem and His Mitzvos, and brings a Korban visibly; he thinks that Hashem does not know his heart. He does not honor Hashem, rather, he disgraces Him.
Malbim: You will call, and I will save you, and you will bring to Me other Korbanos for this. This is like one who is hungry, and requests that one give to him to eat. Due to this, he is obligated to help the one who feeds him, and to be ready to fulfill his desire constantly, so the other will always satiate his hunger.
What is the meaning of "u'Sechabedeni"?
Rashi: This is My honor, that I save those who trust in Me.
Radak: Refer to 50:15:1:1.
Radak (91:15, based on Shocher Tov 91:8): Asaf said 'one whom I (Hashem) save, he must honor Me.' Moshe said (91:15) "Achaletzehu va'Achabedehu" - I (Hashem) will save him and honor him!
