As a student of Taekwon-Do:

I shall observe the tenets of Taekwon-Do
I shall respect the Instructor and Seniors
I shall never misuse Taekwon-Do
I shall be a champion of freedom and justice
I shall build a more peaceful world

Tenets of Taekwondo: Courtesy, Integrity, Perseverance, Self-Control and Indomitable Spirit.

Significance of Belt Colours 

Signifies innocence, as that of the beginning student who has no previous knowledge of Taekwon-Do.

Signifies Earth, from which a plant sprouts and takes root as the Taekwon-Do foundation is being laid.

Signifies the plant's growth as the Taekwon-Do skill begins to develop.

Signifies the heaven, towards which the plant matures into a towering tree as training in Taekwon-Do progresses.

Signifies danger, cautioning the student to exercise control and warning the opponent to stay away.

Opposite of white, therefore, signifying the maturity and proficiency in Taekwon-Do. It also indicates the wearer's imperviousness to darkness and fear.