Says Rabbi Avigdor Miller.
Here’s an excerpt:
… And that’s why the avodas hakorbanos is one of the pillars that support the world:על שלשה דברים העולם עומד – “On three things the world stands” (Avos 1:2), and one of them is the avodah. You know, some people say that avodah means korbanos also; yes, of course, that too. They won’t deny that. But the true avodah, they’ll tell you, is tefillah. But that is wrong. The avodah that is meant here, the pillar of the world – is korbanos, animal sacrifice; only that today, because we have no choice, so tefillah stands in place of korbanos (Berachos 26b).And that’s why we’re not satisfied today with what we have because we want the real thing. We say ברוך אתה השם שומע תפלה – “Yes, Hashem, You listen to our tefillos; I know that you’re listening when I speak to You.” And that avodah she’bileiv is so important. And yet, what’s the next thing we say right away? רצה השם אלוקינו בעמך ישראל והשב את העבודה – “Please return to us the avodah of korbanos.” We’re not satisfied with tefillah, with the avodah of the heart. We want the real thing; we’re asking for the avodas hakorbanos, for the opportunity to bring up animals onto the fire of the mizbei’ach. And therefore when you finish shemonah esrei, you feel like a person who ate a meal without anything solid, you’re not full yet. And so you say יהי רצון מלפניך השם אלוקינו שיבנה בית המקדש – Hashem, give us back the avodah once more. Then we’ll be serving You for real! …