Baptism represents the death, burial and resurrection of Christ.
Mat 3:16 And Jesus, when he was baptized, went up straightway out of the water: and, lo, the heavens were opened unto him, and he saw the Spirit of God descending like a dove, and lighting upon him:
Mat 3:17 And lo a voice from heaven, saying, This is my beloved Son, in whom I am well pleased.
Baptism washes away our sins, however Jesus was sinless.
Jesus' ministry begins with 40 days of fasting, then Satan tries to tempt Him.
Why did Jesus start His earthly ministry by being baptized by John the Baptist who was a Levite?
Amos 3:7 Surely the Lord GOD will do nothing, but he revealeth his secret unto his servants the prophets.
Was the LORD GOD revealing a secret at the baptism of Jesus?
Are there any Torah or other scriptures from the Old Testament that suggest the answer?
Only priests were allowed in the Holy Place.
Luke 1:5 John the Baptist's father, Zechariah, belonged to the priestly division of Abijah/Abia. (1 Chron 24:10) The 8th division/course rotation to serve 8 days Sabbath to Sabbath. A pure blooded priest, a cohanim to the house of Aaron
Luke 1:8-13 Zechariah was performing his priestly duties in the temple, at the alter of incense. When the angel Gabriel appears & tells him this wife Elizabeth (to old for childbirth) would have a son & they will call him John
Scripture proclaims John the Baptist was a prophet & much, much more:
Matt 11:9 Jesus asked, what went ye out for to see? A prophet? yea, I say unto you, and more than a prophet.
(MY NOTE: Jesus says; John the Baptist was a prophet & MORE)
Luke 7:26 Jesus asked, what went ye out for to see? A prophet? Yea, I say unto you, and much more than a prophet.
(MY NOTE: Jesus said; John the Baptist was a prophet & MUCH MORE.)
Here the Lord is instructing Aaron His Chosen High Priest:
Lev 10:9 Do not drink wine nor strong drink, thou, nor thy sons with thee, when ye go into the tabernacle of the congregation, lest ye die: it shall be a statute for ever throughout your generations:
(MY NOTE: Priests of the Levitical order were not to drink wine nor strong drink, throughout their generations)
Here an angel of the Lord is giving Zacharias instructions regarding John the Baptist:
Luke 1:15 For he shall be great in the sight of the Lord, and shall drink neither wine nor strong drink; and he shall be filled with the Holy Ghost, even from his mother's womb.
(MY NOTE: John shall drink neither wine nor strong drink & shall be filled with the Holy Ghost, even from his mother's womb.)
God ordained/chose (Ex 28:1-2) Aaron, Moses elder brother. As High Priest (Num 17:7-8) & had him offer Two sacrifice's of atonement, on the 10th day of the 7th month, the Day of Atonement. So the yearly sins of Israel could be covered (not taken away Lev 16)
Only the High Priest could transfer/impute sin
God specified that the sacrifice's of the Day of Atonement could only be offered by Aaron & the succeeding High Priests among his descendants. Two sacrifices were offered. A lot was drawn, one was sacrificed to the Lord. The other (Azazel Scapegoat) was then sent into the WILDERNESS. Carrying away all the people sins imputed onto it. (Lev 16:8-10, 21 & 22). The people could SEE their sins being carried away.
Lev 16:21 And Aaron shall lay both his hands upon the head of the live goat, and confess over him all the iniquities of the children of Israel, and all their transgressions in all their sins, putting them upon the head of the goat, and shall send him away into the wilderness

see Lev 16:8,9,10,21 & 22 on transfer process).
John the Baptist confessed/announced: Behold the Lamd of God, that TAKES AWAY THE SINS OF THE WORLD. John then layed his hands on Jesus & baptized Him.
Where did Jesus go immediately after His baptism? Answer: The WILDERNESS! (Mk 1:12) Only the High Priest could inact this sin transfer process. (see scapegoat Lev 16:10)
Jesus was both sacrifices! People are free to draw their own conclusions, I believe, like Aaron (the 1st), John was chosen by God as (the last) earthly High Priest.