Vayikra may be the least accessible book of the Torah. Perhaps by examining several reasons the Torah, our Sages and modern scholars have put forth for why there were animal sacrifices, we may find an entry point into the themes of this book.
(4) and Abel, for his part, brought the choicest of the firstlings of his flock. The LORD paid heed to (accepted) Abel and his offering,
(ב) וכמו זאת ההנהגה בעצמה מן המנהיג ההוא ית' באו דברים רבים בתורתנו - והוא שאי אפשר לצאת מן ההפך אל ההפך פתאום - ולזה אי אפשר לפי טבע האדם שיניח כל מה שהרגיל בו פתאום. וכאשר שלח האלוה 'משה רבנו' לתתנו "ממלכת כהנים וגוי קדוש" בידיעתו ית' - כמו שבאר ואמר "אתה הראת לדעת וגו'" וידעת היום והשבות אל לבבך וגו'" ולהנתן לעבודתו - כמו שאמר "ולעבדו בכל לבבכם" ואמר "ועבדתם את יי אלוקיכם" ואמר "ואותו תעבודו" - והיה המנהג המפורסם בעולם כולו שהיו אז רגילים בו והעבודה הכוללת אשר גדלו עליה - להקריב מיני בעלי חיים בהיכלות ההם אשר היו מעמידים בהם הצלמים ולהשתחוות להם ולקטר לפניהם
(2) Many precepts in our Law are the result of a similar course adopted by the same Supreme Being. It is, namely, impossible to go suddenly from one extreme to the other: it is therefore according to the nature of man impossible for him suddenly to discontinue everything to which he has been accustomed. Now God sent Moses to make [the Israelites] a kingdom of priests and a holy nation (Exod. 19:6) ...The Israelites were commanded to devote themselves to His service; comp. "and to serve him with all your heart" (ibid. 11:13); "and you shall serve the Lord your God" (Exod. 23:25); "and ye shall serve him" (Deut. 13:5). But the custom which was in those days general among all men, and the general mode of worship in which the Israelites were brought up, consisted in sacrificing animals in those temples which contained certain images, to bow down to those images, and to burn incense before them; -Maimonides
Nachmanides comments on Maimonides:
When Noah and his sons came out of the Ark, there was not a Babylonian or an Egyptian on the face of the earth. Yet he offered sacrifice and God found it good (Gen. 8:21)
R. David Hoffman on Abraham's sacrifice of a ram instead of his son Isaac.
"This experience illustrates the idea of full submission and total obedience to the Divine will, which is the ultimate purpose of man's life--through an animal sacrifice. This is the compliance that God demands of us, this is what "fear of God" means...
We all make sacrifices for our work
What sacrifices do you make?
Why do you make these sacrifices? What makes it worth it?
Alternatively
If prayer is a substitute for animal sacrifice (See Avot D’rabbi Natan Chapter 4), how can we bring the same intensity/awe to prayer as may have accompanied animal sacrifice.