Philaret of Moscow elucidates, "a baptism in the blood shed on the Cross." The inquiry posed to the sons of Zebedee compelled them to reflect on whether they were prepared to endure the sufferings and the cross of Christ, rather than simply expecting glory. The Lord remarked, "You speak of honor and crowns, but I direct your attention to the trials and efforts that await you: the time for reward has not yet arrived, and My glory is not revealed at this moment; the present is a time marked by death, struggle, and peril" (St. John Chrysostom).
Events to follow indicated how unprepared the disciples were to share in the cup and baptism of the Divine Redeemer (Mk. 14:50). Still, "in the fervor of their zeal," as the holy father notes, consumed by a desire to respond affirmatively, James and John declared, "We can," unaware of the implications of their words. The Omniscient One understood that this response, given without full awareness, would ultimately find its fulfillment. Consequently, He foretold both apostles the destinies that awaited them, while clarifying that heavenly rewards are given to those who endure until the end (Matt. 24:13) and triumph over all trials (Rev. 3:21). "The cup I drink, I drink; and the baptism I receive, I receive; but to sit at My right hand or at My left is not Mine to grant - that privilege is reserved by My Father." It is not for me, a righteous judge, to bestow such honor out of mere affection without merit; otherwise, I would cease to be just. This type of honor is designated only for those who strive diligently (Blessed Theophylact). As Venerable Isidore Pelusiot emphasizes, I cannot bestow such gifts simply upon request, nor can I reward those who do not labor for them.
Heavenly rewards are intended for all who have faith and express their belief through good works. These will be allocated at the Last Judgment by Christ the King in accordance with the Father's will, who has entrusted the Son with all judgment (Matthew 25:31-46; John 5:22). As St. Basil the Great states, "It is up to those receiving the reward to be deemed worthy to sit at the right hand of the Lord, not the one who can bestow it, even if the request is unwarranted." Sitting at the right hand of the ineffable majesty of God, as it is said of the Lord seated at God's right (Mk. 16:19), according to St. John Chrysostom, is accessible to no one; this includes not only humans, such as saints and apostles, but also angels, archangels, and all higher powers. The Church visually represents the architecture of salvation in icons, where the Most Holy Mother of God, as Queen, and St. John the Baptist, the greatest of all prophets, stand at the right hand of the Throne of God’s Majesty.