Albert Barnes, Commentary on John 17
It is a matter of unspeakable joy that each Christian, however humble or unknown to men—however poor, unlearned, or despised, can reflect that he was remembered in prayer by him whom God heareth always. We value the prayers of pious friends. How much more should we value this petition of the Son of God! To that single prayer we who are Christians owe infinitely more real benefits than the world can ever bestow; and in the midst of any trials we may remember that the Son of God prayed for us, and that the prayer was assuredly heard, and will be answered in reference to all who truly believe. All may be one. May be united as brethren. Christians are all redeemed by the same blood and are going to the same heaven. They have the same wants, the same enemies, the same joys. …. Hence they should feel that they belong to the same family, and are children of the same God and Father. There are no ties so tender as those which bind us in the gospel. There is no friendship so pure and enduring as that which results from having the same attachment to the Lord Jesus. Hence Christians, in the New Testament, are represented as being indissolubly united—parts of the same body, and members of the same family, Acts 4:32–35; 1 Cor. 12:4–31; Eph. 2:20–22; Rom. 12:5. On the ground of this union they are exhorted to love one another, to bear one another’s burdens, and to study the things that make for peace, and things wherewith one may edify another, Eph. 4:3; Rom. 12:5–16.