פַּ֣ר אֶחָ֞ד בֶּן־בָּקָ֗ר אַ֧יִל אֶחָ֛ד כֶּֽבֶשׂ־אֶחָ֥ד בֶּן־שְׁנָת֖וֹ לְעֹלָֽה׃
satu ekor lembu jantan muda, satu ekor domba jantan, satu ekor anak domba jantan berumur setahun, sebagai korban bakaran;
Chizkuni
בן שנה, “within the first year of its life.” We have proof that this is the meaning of the expression: בן שנה, from when the princes offered their offerings during the consecration rites of the Tabernacle in Numbers 7,15 and elsewhere, as the Torah there describes each of these lambs as בן שנתו, “during the first year of its life.” At the end the Torah repeats that they offered 12 lambs each “in the first year of its life,” i.e. בני שנה.
Rabbeinu Bahya
ויהי לתנין, “it turned into a snake.” This was the first of the many miracles Moses performed for Pharaoh. The word תנין, means serpent; we know this from verse 15 where G’d referred to Moses’ staff as having turned into a נחש, a snake. The reason the staff turned into a snake and not into some other animal was that the snake had been the first creature to introduce sin by seducing Chavah with its tongue. Pharaoh had also sinned with his tongue, when he refused to recognize the existence of the G’d of Israel and used this pretext to add that he was not obligated to obey a deity he had never heard of. Just as the serpent at the time had been punished, so Pharaoh starts being punished.
It has become accepted norm that when one slanders G’d or His existence, one is bitten by snakes as we know from Numbers 21,5 “the people spoke out against G’d and Moses“ which is followed by (21,6) ”G’d sent fiery serpents against the people and they bit the people.” Furthermore, just as a snake can make itself rigid and wriggle out of unpleasant situations, so Pharaoh squirmed and on other occasions remained rigid in order to avoid having to obey G’d’s wishes. Whenever the plagues got the better of him he seemed to relent in order to gain relief only to renege in the hope that G’d had exhausted His power. He would resume his obstinate stance of refusing to let the Israelites go. The reason that this נחש is called תנין in our verse is that Pharaoh has been referred to elsewhere as the התנים הגדול הרובץ בתוך יאוריו, “the great sea-monster that crouches within its rivers” (Ezekiel 29,3). The word תנין here contains a hint that just as the staff of Aaron swallowed all the staffs of the Egyptian magicians so the sea (G’d) would swallow Pharaoh and his army at the sea of Reeds.
It has become accepted norm that when one slanders G’d or His existence, one is bitten by snakes as we know from Numbers 21,5 “the people spoke out against G’d and Moses“ which is followed by (21,6) ”G’d sent fiery serpents against the people and they bit the people.” Furthermore, just as a snake can make itself rigid and wriggle out of unpleasant situations, so Pharaoh squirmed and on other occasions remained rigid in order to avoid having to obey G’d’s wishes. Whenever the plagues got the better of him he seemed to relent in order to gain relief only to renege in the hope that G’d had exhausted His power. He would resume his obstinate stance of refusing to let the Israelites go. The reason that this נחש is called תנין in our verse is that Pharaoh has been referred to elsewhere as the התנים הגדול הרובץ בתוך יאוריו, “the great sea-monster that crouches within its rivers” (Ezekiel 29,3). The word תנין here contains a hint that just as the staff of Aaron swallowed all the staffs of the Egyptian magicians so the sea (G’d) would swallow Pharaoh and his army at the sea of Reeds.
Ibn Ezra
The Dissenters claim that yearling does not mean “a year old” [cf. comment on 12:6]. The former, according to them, denotes an animal under one year of age, whereas the latter denotes an animal one year old or older. The passage dealing with the dedication of the Altar, however, speaks of “one yearling lamb” [Numbers 7:15], yet in the end gives a total count of “twelve one-year lambs” [Numbers 7:87].