Does Colombia have a national pledge?

Yes, Colombia does have a national pledge. Here is the Spanish version of the pledge with an English translation:

Juramento a la Bandera

Juro delante de Dios y de la Bandera de mi patria, ser fiel a ella, a sus instituciones democráticas y a sus sí­mbolos.

Defenderé con honor la integridad territorial, el orden constitucional, la soberaní­a y la independencia de Colombia.

Serviré con lealtad su causa y con respeto acataré sus Leyes.

Trabajaré por su engrandecimiento y prosperidad, y haré cuanto dependa de mi para que su nombre sea respetado en el ámbito internacional.

Que Dios me ayude a cumplir este juramento.

Pledge to the Flag

I swear before God and the Flag of my country, to be faithful to it, to its democratic institutions and to its symbols.

I will defend with honor the territorial integrity, the constitutional order, the sovereignty and independence of Colombia.

I will serve its cause with loyalty and with respect I will obey its laws.

I will work for its greatness and prosperity, and I will do everything in my power so that its name may be respected in the international sphere.

May God help me to fulfill this oath.