Hebrew meaning of Matthew 3:17 "This is my Son, whom I love; with him I am well pleased."

And a voice from heaven said, "This is my Son, whom I love; with him I am well pleased."
- Matthew 3:17

UNDERSTANDING BAPTISM IN CHRIST'S DAY
In Matthew 3, Jesus is being baptized by John the Baptist.  Baptism was first practiced in Hebrew culture as a ceremonial cleaning and was later adopted by Christians.  Baptism in the Hebrew customs signified a person's willingness to dedicate their lives to God in a public profession.  So it is a custom that has also become part of the Christian faith.  In Christianity, after accepting Christ as Lord and Savior, a Believer is baptized as a public profession of faith.  The word baptism in Hebrew MIKVEH means immersion.  There are some variations in how this is done in varying Christian denominations but it always symbolizes faith in Christ Jesus and immersion or filling of the Believer with the Holy Spirit.  To the Christian, God, Jesus and the Holy Spirit are three distinct persons yet form the complete being of the triune God.  This triune God is referred to as the Trinity.  For the Christian, baptism is really a public announcement of the belief in the Triune God with Jesus interceding to the Father and the Holy Spirit indwelling this new believer at salvation.  So in many ways, baptism today is for the same reasons as in the Hebrew culture with the exception of acceptance of Christ as Messiah.  Jesus was baptized by John in obedience to God.

BAPTISM OF JESUS BY JOHN THE BAPTIST
John the Baptist was the one in scripture foretold of who would announce the coming of the Messiah.  Isaiah 40:3 foretold of John stating,  A voice of one calling: "In the wilderness prepare the way for the LORD; make straight in the desert a highway for our God.  We see this again in Matthew 3:3 confirming that John fulfilled this scripture.  He knew the Messiah was to come and was baptizing other in preparation for the coming Messiah.  John himself did not know who the Messiah would be, but God had given his sign for John to recognize Him.  The Messiah, unlike other men, would have the Holy Spirit come upon him and remain in him.  The Holy Spirit at that time came upon men like Elijah and other prophets; however, it never remained on a man for long.  It was not until Pentecost that the Holy Spirit first began to indwell Believers.  So we learn from Scripture that Jesus came to John to be baptized.  Upon baptism, the Holy Spirit came to rest upon Jesus and remained.  This was John's proof of Jesus's deity as the promised Messiah.  It was during this Baptism that God spoke.  The words God spoke are clearly recorded in Matthew 3:17.

SIGNIFICANCE OF MATTHEW 3:17
Most Christians gather that Jesus's baptism was no ordinary baptism as the Holy Spirit came to permanently rest upon him and a voice spoke from heaven.  What most Believers don't realize is that the words spoken had significant meaning in Hebrew culture.  When God said, "This is my Son, whom I love, with whom I am well pleased", it is interpreted as yet another proof of Jesus's diety.  These exact same words were commonly uttered at Barmitzvahs of the day.  A barmitzvah is a Jewish blessing ceremony recognizing a boy's passage from childhood into adulthood and the beginning of religious responsibility.  In a barmitzvah, there is a point in the ceremony where all the men raise this one young man to their shoulders.  At this point, only one adult male can give the blessing.  This man cannot be the stepfather, uncle, brother or anyone else.  Only the blood father can say, "This is my Son, whom I love, with whom I am well pleased."  God is revealing and affirming to a Hebrew culture whom Jesus is.  Jesus is the Son of God.  God is the blood father.  Jesus himself says that he came from the Father and is going back to the Father in John 16:28.  So God is Jesus's Father and Jesus is the Son of God.

I hope that both the discussion of baptism and barmitzvah in Hebrew culture helped you gain greater insight into Christian scriptures.