A while back, I had heard a story from Gandhi's life that gave me goosebumps. "My greatest weapon is a mute prayer," he used to say.
I happened to be leafing through page 418 of Rajmohan Gandhi's biography of Gandhi and thought I'd post the full account as it appears in the book:

There was talk of threat to Sardar Vallabh Patel's life. Then, on 16 April, a 600-strong mob of sword-swinging and lathi-carrying Muslims broke up a prayer meeting that a barely fit Gandhi, some months shy of his 70th birthday, was conducting in Rajkot, a tried forcibly to disperse a cordon of unarmed volunteers around Gandhi.

Remaining at Gandhi side, Kalelkar's 26-year-old son Bal, who had been a Dandi marcher in his teens, 'suddenly noticed that Bapuji's whole body began to shake violently'. Bal Kalelkar thought that the shaking:

was not out of fear; his face could tell how free from fear he was. The physical reaction was his revolt against the disgusting atmosphere of violence.

Pyarelal, who was not far, wrote what we have already quoted. He would say that the shaking was set off by a sudden attack of sharp pain near the waist, 'an old symptom that seizes him whenever he receives an acute mental shock.' Added Pyarelal:

For a time he stood in the midst of that jostling crowd motionless and silent, his eyes shut, supporting himself on his staff, and tried to seek relief through silent prayer ... As soon as he had sufficiently recovered, he reiterated his resolve to go through the demonstrators all alone. He addressed a Bhayat, who stood confronting him: "I wish to go under your sole protection, not co-workers."

Bal Kalelkar's account suggests that this time the prayer was not silent, that Gandhi cried out to God:

Suddenly he closed his eyes and started praying. I could hear him saying Ramnam with an intensity of devotion that could never be surpassed. I join him in his prayer and to keep time to our chanting of God's name I started patting my hand on his back ...

The prayer worked. When Bapuji reopened his eyes there was a new strength that appeared then like magic. In a firm tone, he asked all volunteers to quit that place at once and leave him aboslutely alone at the mercy of the hired goonda (thugs) ...

Then he called the leader of the gang who was busy breaking up the congregation and told him that he was absolutely at his disposal if he cared to argue out his point; if not, would he tell what he proposed to do next? To everyone's amazement the thugs' violence melted like ice. The leader of the gang stood before Bapuji with folded hands ... That evening he walked all the way home with one hand on the shoulder of the leader of the gang.