John 17:21 "that they all may be one, as You, Father, are in Me, and I in You; that they also may be one in Us, that the world may believe that You sent Me. 22 "And the glory which You gave Me I have given them, that they may be one just as We are one: 23 "I in them, and You in Me; that they may be made perfect in one, and that the world may know that You have sent Me, and have loved them as You have loved Me. 24 "Father, I desire that they also whom You gave Me may be with Me where I am, that they may behold My glory which You have given Me; for You loved Me before the foundation of the world. 25 "O righteous Father! The world has not known You, but I have known You; and these have known that You sent Me. 26 "And I have declared to them Your name, and will declare it, that the love with which You loved Me may be in them, and I in them."(NKJV)
In this section we see Jesus saying He has given us His glory that we will be one. The earthly sufferings of our Lord are part of His glory (John 12:23; 13:31-32; 17:1). And it is this glory—the glory of servant hood and of sacrificial service, which our Lord has given to us, His disciples. As Jesus was glorified by His coming to this earth, being rejected by men and put to death, so His disciples are also given the same glory, the glory of suffering for the sake of Christ: Secondly, He prays for us to have the same love that the Father loves the Son with. This is a love which will prompt one to lay down his life for his friends (John 15:13).
John 17:20 "I do not pray for these alone, but also for those who will believe in Me through their word; 21 "that they all may be one, as You, Father, are in Me, and I in You; that they also may be one in Us, that the world may believe that You sent Me.
Here Jesus is still praying for us believers and is praying again that we would be one as the He is with the Father and the Holy Spirit. They never fight over who gets to be the Father, who gets to be the Son or the Holy Spirit. They are always one and in unison on everything because they have one purpose as we do also. He is praying that we would be one in Them, THAT (here is the purpose) the world may believe that Jesus was sent by the Father and when they do that they will be saved. That is it people, when we believe Jesus is who He said He was (God in Human Flesh), that He died for our sins, and we trust in that, we are saved. John 5:24 says if we don’t honor the Son, we don’t honor the Father. When we live as we ought to in harmony with our faith others believe in Jesus.
John 17:13 "But now I come to You, and these things I speak in the world, that they may have My joy fulfilled in themselves. 14 "I have given them Your word; and the world has hated them because they are not of the world, just as I am not of the world. 15 "I do not pray that You should take them out of the world, but that You should keep them from the evil one. 16 "They are not of the world, just as I am not of the world. 17 ¶ "Sanctify them by Your truth. Your word is truth. 18 "As You sent Me into the world, I also have sent them into the world. 19 "And for their sakes I sanctify Myself, that they also may be sanctified by the truth.
Jesus has spoken many things so we can have His joy complete in our life. We are also told how we have the Father’s word and because of that we will be hated because we are not like the world. He prays for us not to be taken out of the world, but that we will be protected while we are here. Our job is not to get saved and leave, but we are to share God’s word with others. He also is praying that we will be Holy and separate from the world because we have been transformed by the Word we have read and absorbed into our life. He also sends us as He was sent and has set Himself apart as completely holy so that we can be that way too.