What made Son Goku so strong?

Son Goku is one of the few survivors of Sayan Planet after it was destroyed by Frieza. He was sent to earth and was originally evil but he fell on a cliff which totally overhauled his personality. Son Gohan, a skilled martial artist was the one who adopted and raised Son Goku. Later on, he was trained by Master Yoshi, the strongest martial artist in the world during his time. Many people claim that Son Goku is strong just because of his absurd amount of ki (inner power). I believe that Son Goku’s power lies on his conviction for peace and justice. He will do everything, even risk his own life just to protect the innocent and keep the people close to his heart away from danger. He won’t back out on any fight despite being assured of an imminent defeat. Here are a few pictures of Son Goku for every Dragonball Z fanatic out there:

Son Goku Super Sayan 2

Son Goku Super Sayan 1, 2, 3

Son Goku Super Sayan 4

Son Goku creating an Energy Ball