During times of persecution, Jews were often prohibited from performing commandments or praying to the One above. Such a scenario took place during the years prior to the Spanish Inquisition, when countless Jews were forced to practice Judaism while hidden. It is said that the gentiles prohibited all types of prayer to God, if it wasn't to the Christian deity. Jews were not allowed, hence, to recite Birkat Hamazon. In its place, Jews of Spain composed this poem to thank God for providing them with their sustenance.
Thankfully, we are no longer under the whips of the gentiles and therefore we are able to freely recite Birkat HaMazon whenever we wish. However, until today, some Jews in Spanish cities in North Africa, along with the entire Sephardic community of Gibraltar, have kept the practice to recite this hymn.
In order that it should not take the rightful place of Birkat Hamazon, Jews of Gibraltar sing "Bendigamos" after the recital of Birkat HaMazon.
It's a gorgeous melody, and I'm proud to record it, hopefully, with the same accuracy as my fellow brothers in Gibraltar.