May we look deeper into the passage before us (Jn 6:37-40).
v37 "All [singular neutral gender 'pan'] that the Father gives to Me . . ."
v39 "of all [singular neutral gender 'pan'] that He has given Me . . ."
The singular neutral gender in those two instances suggests that Jesus is referring to the whole of what the Father gives to Him. He is referring to the Church in its entirety, to His Body as a singular whole.
And for this reason, any member of His body rightly perceives these statements as directed to them: "I will in no way cast out" (Jn 6:37), "I shall not lose any" (Jn 6:39), "shall raise it up" (Jn 6:39), and "should have everlasting life" (Jn 6:40) .
While I agree that it refers to the whole of those the Father gave Him, I disagree that it's a reference to the church. Consider Jesus's words in John 17.
KJV John 17:1 These words spake Jesus, and lifted up his eyes to heaven, and said, Father, the hour is come; glorify thy Son, that thy Son also may glorify thee: 2 As thou hast given him power over all flesh,
that he should give eternal life to as many as thou hast given him. 3 And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent. 4 I have glorified thee on the earth: I have finished the work which thou gavest me to do. 5 And now, O Father, glorify thou me with thine own self with the glory which I had with thee before the world was. 6 I have manifested thy name
unto the men which thou gavest me out of the world: thine they were, and
thou gavest them me; and they have kept thy word. 7 Now they have known that all things whatsoever thou hast given me are of thee. 8 For I have given unto them the words which thou gavest me; and they have received them, and have known surely that I came out from thee, and they have believed that thou didst send me. 9 I pray for them: I pray not for the world, but for
them which thou hast given me; for they are thine. 10 And all mine are thine, and thine are mine; and I am glorified in them. 11 And now I am no more in the world, but these are in the world, and I come to thee. Holy Father, keep through thine own name
those whom thou hast given me, that they may be one, as we are. 12 While I was with them in the world, I kept them in thy name:
those that thou gavest me I have kept, and none of them is lost, but the son of perdition; that the scripture might be fulfilled. 13 And now come I to thee; and these things I speak in the world, that they might have my joy fulfilled in themselves. 14 I have given them thy word; and the world hath hated them, because they are not of the world, even as I am not of the world. 15 I pray not that thou shouldest take them out of the world, but that thou shouldest keep them from the evil. 16 They are not of the world, even as I am not of the world. 17 Sanctify them through thy truth: thy word is truth. 18 As thou hast sent me into the world, even so have I also sent them into the world. 19 And for their sakes I sanctify myself, that they also might be sanctified through the truth. {sanctified...: or, truly sanctified} 20 Neither pray I for these alone, but for them also which shall believe on me through their word; 21 That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me. 22 And the glory which thou gavest me I have given them; that they may be one, even as we are one: 23 I in them, and thou in me, that they may be made perfect in one; and that the world may know that thou hast sent me, and hast loved them, as thou hast loved me. 24 Father, I will that they also,
whom thou hast given me, be with me where I am; that they may behold my glory, which thou hast given me: for thou lovedst me before the foundation of the world. 25 O righteous Father, the world hath not known thee: but I have known thee, and these have known that thou hast sent me. 26 And I have declared unto them thy name, and will declare it: that the love wherewith thou hast loved me may be in them, and I in them. (Joh 17:1 KJV)
Notice Jesus' words in the past tense, 'those thou gavest me.' Those given to Jesus was a specific group of men for the purpose which God had for them. There is nothing else in the Scriptures about anyone else being given to Christ. None of the apostles speak of believers being given to Christ (except for Jesus word there).