The motif of the gift of the elect to the Son is expressed by Jesus on various occasions, particularly in the Gospel of John:
This is the will of the Father who sent Me, that of all He has given Me I should lose nothing, but should raise it up at the last day. And this is the will of Him who sent Me, that everyone who sees the Son and believes in Him may have everlasting life; and I will raise him up at the last day. (6:39-40)
In this passage Jesus makes it clear that He is concerned about every believer being raised up at the last day. This qualifies His statements about what the Father has given Him that would never be lost. It is believers who are given to Christ by the Father, and these believers will never be lost. This affirmation builds upon what Jesus declared only moments earlier:
But I said to you that you have seen Me and yet do not believe. All that the Father gives Me will come to Me, and the one who comes to Me I will by no means cast out. For I have come down from heaven, not to do My own will, but the will of Him who sent Me. (6:36-38)
Jesus is emphatic in His assertion that all whom the Father gives to Him will in fact come to Him. The order here is crucial. Jesus does not say that all who come to Him will then be given to Him by the Father. We do not determine by our response who will be the Father's gift to the Son. Rather our response is determined by the prior election of God for us to come to the Son as gifts to Him.
The concept of believers being the gifts of the Father to the Son forms a central element of Jesus' high-priestly prayer in John 17. Jesus makes repeated references to this "giving":
Father, the hour has come. Glorify Your Son, that Your Son also may glorify You, as You have given Him authority over all flesh, that He should give eternal life to as many as You have given Him. (vv. 1-2)
Christ speaks of the authority He has received from the Father to grant eternal life to certain people. Those certain people are the ones the Father has given to Him.
I have manifested Your name to the men whom You have given Me out of the world. They were Yours, You gave them to Me, and they have kept Your word. Now they have known that all things which You have given Me are from You. For I have given to them the words which You have given Me; and they have received them, and have known surely that I came forth from You; and they have believed that You sent Me.
I pray for them. I do not pray for the world but for those whom You have given Me, for they are Yours. And all Mine are Yours, and Yours are Mine, and I am glorified in them. Now I am no longer in the world, but these are in the world, and I come to You. Holy Father, keep through Your name those whom You have given Me, that they may be one as We are. While I was with them in the world, I kept them in Your name. Those whom You gave Me I have kept; and none of them is lost except the son of perdition, that the Scripture might be fulfilled. (17:6-12)
In this prayer it is clear that believers are the Father's gift to the Son, a gift that is not to be lost or destroyed. Jesus prays that these gifts may be kept and not discarded. He thanks the Father that all have been kept except the son of perdition, who is elsewhere described as having been a devil from the beginning. The son of perdition refers here to Judas.
The concept of our adoption in Christ as the Father's gift to the Son is also declared by the author of Hebrews:
For it was fitting for Him, for whom are all things and by whom are all things, in bringing many sons to glory, to make the captain of their salvation perfect through sufferings. For both He who sanctifies and those who are being sanctified are all of one, for which reason He is not ashamed to call them brethren, saying:
"I will declare Your name to My brethren;
In the midst of the assembly I will sing praise to You."
"I will put My trust in Him."
"Here am I and the children whom God has given Me." (2:10-13)
This text confirms that the elect are given to Christ as His adopted brothers and the Father's adopted children. This is the astonishing love that would provoke John to utter later, "Behold, what manner of love is this?"