Christians are followers of Christ ( he is the central character of our faith so it is important we understand who he is.
His full title is the Lord Jesus Christ, e.g. Ephesians 1:3.
Lord - applied in the Old Testament to God. This title is applied to Jesus in the N.T. and indicates his deity.
Jesus = Jehovah is salvation. Jesus = Saviour. Matthew 1:21
A summary of the Bible's teaching on the Lord Jesus is he has two natures, divine and human, which concur in one Person.
The Bible teaches that Jesus is God, God the Son
Names and titles imply full deity
The O.T. title of LORD is applied to Jesus in the N.T.
In Isaiah 9:6 clearly the Messiah is in view but addressed as God.
He is called God
Attributes of God are applied to him
Works of God are ascribed to Christ
Worship is given to him
When it comes to describing the deity of Christ, the creeds put it like this:
'Christ is consubstantial, of the same substance and essence of the Father, co-equal, co-eternal, begotten, not made.'
The Bible teaches Jesus is fully human
[Note: Jesus Christ was subordinate in his role as Saviour and mediator to his Father, 1 Corinthians 15:22-28]
Why did Christ need to be God?
The human problem of sin means we need divine Saviour to:
Why did he also need to be human?
Man sinned, therefore the penalty had to be borne by a man.
Note: the formula worked out at the Council of Chalcedon AD451 is a good way of understanding the Biblical material:
The two natures concur (are together) in one person. They are not mixed together or changed by their relationship with each other, yet they are without division. Jesus Christ is one person, not two. When he acts, he acts as a single person.
Because Jesus Christ is who he is, he is a suitable and sufficient Saviour.
[Note there have been many false teachings concerning Christ seen in Church history and still present today, e.g. Arianism (which says that God created in his own image the only begotten son) ( J.W.'s hold this view. Many other '-isms' have also distorted the Bible's teaching concerning Christ.]