Christ's gentle reprimand: V. 38. But Jesus said unto them, Ye know not what ye ask; can ye drink of the cup that I drink of? and be baptized with the baptism that I am baptized with? V. 39.And they said unto Him, We can. And Jesus said unto them, Ye shall indeed drink of the cup that I drink of; and with the baptism that I am baptized withal shall ye be baptized; V. 40. but to sit on My right hand and on My left hand is not Mine to give, but it shall be given to them for whom it is prepared.
Jesus here shows a little of the wealth of kind consideration which He is always ready to give to those that sin from weakness. "He deals with them in the most gentle manner, does not give them a harsh word; but instructs them with all kindness that they desist from their request and have other thoughts of His kingdom and their ministry, as a father admonishes his children in all goodness" (Luther, 13a, 1198).
In order to do this, He asks them whether they think they are able to drain the cup of suffering which would shortly be offered to Him, and be baptized with the baptism of blood which would soon be His lot. They answered in the affirmative, not knowing what they were affirming.
"That is Christ the Lord's kingdom, and He Himself, the King in this kingdom, opens the work. He drinks the cup, that is, He suffers, and suffers more and more severely than all His subjects, as we see from His gospel. Such example all those must follow who acknowledge Christ as their Head and Lord, as Paul says to the Romans, 8, 17, that we must become like to the image of the Son of God in suffering, and thereupon in glory" (Luther, 13a, 1203).
The same cup they would not and could not drink, in spite of their protestations. But they would learn to imitate Him in following the road of suffering and death after Him, and for His sake, for that is the Christian's lot and the Christian's distinction, incidentally also his assurance that God is a loving, kind Father.
"For when Christ, our dear Lord, offers us His cup and wants to baptize us with His baptism, that is, when He lays His cross upon us, we are apt to conclude that such cup and baptism is an indication that God is angry with us and does not mean well with us. For thus reason looks upon it: if one is happy and everything goes well, he has a gracious God; but he with whom things do not go well, he has an ungracious God. But here we see that this judgment is wrong. For Christ Himself drinks the cup and permits Himself to be baptized; and yet He is God's dear child, in whom the Father has the highest and greatest pleasure, and with whom He cannot be angry. Now Christ has only the best and kindest intentions toward His Christians, for otherwise He would not have given Himself into death for them.... Therefore the Christians should have no horror of the cross, but should rather (as it is in truth) accept it as a sure sign that they are God's children and in the kingdom of Christ" (Luther, 13a, 1205).
At the same time Christ, gently, but firmly, informs them that the fulfillment is a matter of the majestic counsel of God. He has prepared the places of honor and selected those that are to occupy them. As the entire salvation is a matter of God's mercy, so also are the rewards of mercy. They cannot be distributed as earthly monarchs and rulers dispense their bounty, according to the whim of the moment.