Slaughter it at the opening of the Tent of Meeting.
Meshech Chochmah: The gemara finds in this expression a requirement for the validity of a korban shelamim: it must be slaughtered only after the doors of the Ohel Moed have been opened. (Understandably so. Twice in the next few sections the Torah speaks of slaughter “in front of” the Ohel Moed. The anomalous reference to the “opening” sustains a legal position that the slaughter of the shelamim can only take place when the animal stands before the unobstructed entrance-way of the Ohel, and not just in front of it. ) Similar phraseology indicates that the sprinkling of the blood of the olah also requires that the doors of the Ohel be open.
Now, one part of the avodah of animal korbanos certainly does not require that the doors be open. The burning of the specified limbs of the korban takes place even at night, after the closing of the doors. Putting it all together, we can say that the initial steps of the offering of an animal must take place by day; the conclusion of the avodah can follow even by night.
Why would this be?
One of the themes of korbanos that sits a bit beneath the surface is that the avodah must serve the full Essence of Hashem. Were it not for this requirement, people might subdivide their understanding of Divinity, and aim at one or other of the different elements, attributes, or Names with which our imperfect human minds use to grasp what we really cannot – or, worse yet, to any force subsidiary to Him. The Torah therefore insists that the beginning of sacrificial avodah take place during the daytime period, whose light speaks of illumination and relative clarity about the nature of Divinity, so that it is oriented at the full reality of Hashem. Once the avodah begins on the correct path, all steps that follow are drawn after the initial steps. The concluding burning of the limbs on the altar is therefore permitted at night.
We can easily show that the daytime hours are associated with a clearer, fuller revelation of Hashem’s Self. Hashem spoke to Moshe only by day. In fact, in his time atop Mt. Sinai, Moshe knew how to differentiate between day and night this way. When Hashem spoke with him, he knew it was daytime below; when he had to study alone, he knew it was night. (For this reason, the gemara speaks of the Shechinah standing opposite Torah scholars who study at night. Since the study of Torah is elsewhere likened to the avodah, we might make the mistake of taking the comparison too far, and see learning at night as the equivalent of the burning of the limbs, i.e. a lesser form of avodah, divorced from the greater revelation of Hashem by day. Therefore the gemara makes a point of stating that Torah study is different from animal avodah. “Arise, cry out at night…opposite the Face of Hashem.”Learning Torah at night brings the fuller revelation of Hashem’s Presence which is elsewhere associated only with daytime.
We might look at Chazal’s praise of “evening” Torah study in a different manner. They might refer to the conditions of learning, rather than a time period. They perhaps reserve their praise for learning that takes place occluded from public scrutiny and accolades, privately and modestly, often under difficult circumstances, shrouded, as it were, in darkness.
It is not just the tzniyus and the dedication involved in such learning that make it so special. When we learn for a given purpose, e.g., to achieve honor, or to become an authority, or even to become better people, there is a disconnect between the activity of learning and the achieving of the purpose, which comes only after some time. We therefore do not feel the full sweetness of the learning until we near the goal. Those who learn “at night,” under trying circumstances and away from public adulation, do so because they have no goal and purpose other than bonding with Torah itself! Their reward is instantaneous with their learning. They connect with Hashem, and taste the pleasantness of Divine Torah!
 Based on Meshech Chochmah, Vayikra 3:2
 Zevachim 55B
 Vayikra 8:6, 13
 See Torah Temimah
 Vayikra 1:5
 See Menachos 110A, and Ramban to Vayikra 1:9
 Torah Cohanim 96
 Shemos Rabbah 47:5
 Tamid 32B
 Menachos 110A
 Eichah 2:19