Final answer:
Martin Luther King Jr. gained widespread support due to his eloquent public speaking and his dedication to nonviolent methods of protest, which resonated with diverse groups of people.
Step-by-step explanation:
Two qualities of Martin Luther King Jr. that made him gain widespread support from people of all races, classes, and ages were his eloquent public speaking abilities and his steadfast commitment to nonviolence. King's oratory skills were evident in his famous "I Have a Dream" speech, which articulated his vision for racial harmony and equality in a manner that touched the hearts of many. Additionally, his dedication to nonviolent resistance, demonstrated through organized protests, sit-ins, and marches, drew respect and admiration from a broad audience, appealing to moral and ethical principles.