He saved others, himself he cannot save
This was not so much a concession of theirs, that he had done many saving works, as healing the sick, cleansing lepers, causing the blind to see, and the lame to walk, and raising the dead; but rather a suggestion, that these were only pretensions and illusions; that either they were not really done, or done by the help of the devil; since now he himself was in the utmost extremity, he could not save himself: but of this they might have been convinced by his striking many of them to the ground, that came to apprehend him in the garden, and of which these men were eyewitnesses; and he, as man, could easily have obtained of his Father more than twelve legions of angels that would have rescued him out of their hands: but so it must not be; he came not to save himself, but others, and to save them spiritually and eternally by dying himself.
If he be the king of Israel;
that is, the Messiah, who was promised and expected as a king, as Zion's king, or king of Israel; see ( John 1:49 ) , hence in ( Mark 15:32 ) it is Christ the king of Israel.
Let him now come down from the cross, and we will believe him.
The Persic version reads, "that the people may see, and believe in him"; and the Syriac and Arabic versions, "that we may see, and believe in him", as in ( Mark 15:32 ) . But, alas! they had seen greater things already than this, and yet had not believed. He could easily have caused the nails to have given way, and unloosed himself, and come down, who had done such mighty works among them; and if he had, there is no reason to conclude they would have believed him to be the Son of God, and the true Messiah; for though after this, he did a much greater work, raised himself from the dead, of which they had the fullest evidence, yet they remained unbelieving.