Why did God allow Jesus (as) to be crucified and tortured, even though He had promised to save him?

God kept His promise, and Jesus (as) did not die on the cross. Precisely because he went through this suffering and came out alive, his rescue became a great sign that strengthened the faith of his followers.

God’s promise to Jesus (as) was to save him from the accursed death on the cross. It was not a promise to spare him all suffering. That is an important difference.

No prophet of God had an easy life. Each of them was persecuted, mocked and pressed hard for God’s sake, often so severely that his very survival was a miracle. The verse above describes exactly this. Jesus (as) was no exception. He too had to go through persecution, and in the end he was even nailed to the cross.

That is where the sign lay. If God had simply taken Jesus (as) to safety beforehand, no one would have seen anything special. But that he endured the crucifixion and still came out of it alive and whole was an unmistakable miracle for everyone who knew him. His enemies had done everything to kill him, and they had failed.

This experience changed his followers. Those who had believed in him hesitantly now believed with all their hearts. Afterwards Jesus (as) left the land and migrated, and his disciples set out in full earnest to carry on the message for which he had come.

So the suffering of Jesus (as) is no sign that God abandoned him. It was the way in which God showed His power and His faithfulness. The trial was hard, but the rescue was all the clearer for it.