Why was Jesus baptized?

What is baptism? Baptism is the washing with water in the name of the Father, and of the Son, and of the Holy Spirit. It signifies and seals our ingrafting into Christ and partaking of the benefits of the covenant of Grace and our engagement to be His.
Quite simply, Jesus was baptized so he could enter into the Melchizedek priesthood so He could be the High Priest and offer Himself as a sacrifice for our sins.
In Matthew 3:13-15 it says, "Then Jesus came from Galilee to the Jordan to be baptized by John. But John tried to deter him, saying, iI need to be baptized by you, and do you come to me?' Jesus replied, 'Let it be so now; it is proper for us to do this to fulfill all righteousness.'" Jesus got baptized to fulfill all righteousness.

Exodus 29:1-7, "This is what you are to do to consecrate them, so they may serve me as priests: Take a young bull and two rams without defect. And from fine wheat flour, without yeast, make bread, and cakes mixed with oil, and wafers spread with oil. Put them in a basket and present them in it -- along with the bull and the two rams. Then bring Aaron and his sons to the entrance to the Tent of Meeting and wash them with water. Take the garments and dress Aaron with the tunic, the robe of the ephod, the ephod itself and the breast piece. Fasten the ephod on him by its skillfully woven waistband. Put the turban on his head and attach the sacred diadem to the turban. Take the anointing oil and anoint him by pouring it on his head."

Oil is a type of the Holy Spirit: "But you have an anointing from the Holy One, and all of you know the truth...As for you, the anointing you received from him remains in you, and you do not need anyone to teach you. But as his anointing teaches you about all things and as that anointing is real, not counterfeit -- just as it has taught you, remain in him," (1 John 2:20,27).
The Holy Spirit descended from heaven as a dove and rested upon Jesus (Matt. 3:16).
Jesus was baptized because He had to fulfill the legal requirements for entering into the priesthood. He was priest after the order of Melchizedek (Psalm 110:4; Heb. 5:8-10; 6:20). Priests offered sacrifice to God on behalf of the people. Jesus became a sacrifice for our sin (1 Pet. 2:24; 2 Cor. 5:21) in His role as priest.
To be consecrated as a priest, He had to be:

• Washed with water (Lev. 8:6; Exodus 29:4, Matt. 3:16).
• Anointed with oil (Lev. 8:12; Exodus 29:7; Matt. 3:16).

Both of these were bestowed upon Jesus at His baptism.
Additionally, He may have needed to be 30 years old - (Num. 4:3) which is fulfilled in Luke 3:21-23, "Now it came about when all the people were baptized, that Jesus also was baptized, and while He was praying, heaven was opened, 22 and the Holy Spirit descended upon Him in bodily form like a dove, and a voice came out of heaven, “Thou art My beloved Son, in Thee I am well-pleased.” 23 And when He began His ministry, Jesus Himself was about thirty years of age, being supposedly the son of Joseph, the son of Eli..."

• Exodus 29:1 - "This is what you are to do to consecrate them, so they may serve me as priests: Take a young bull and two rams without defect."
• Exodus 29:4 - "Then bring Aaron and his sons to the entrance to the Tent of Meeting and wash them with water."
• Exodus 29:7 - "Take the anointing oil and anoint him by pouring it on his head."

"Surely the Sovereign LORD does nothing without revealing his plan to his servants the prophets," (Amos 3:7). 

For more information, Prayers and counseling you can contact,

Rev. Adbhuta Rao. Garnepudi
Millinium Baptist Church
Nambur, Guntur (Dist), A.P
milliniumbaptistchurchministries@yahoo.com
mbcministries.india@gmail.com
(+91)9848150491, 9908054910