Below is a short audio clip of Giani Baba Inderjit Singh Ji explaining the uthankaa [historical context] behind a shabad written by Guru Amar Daas Ji in Gauree Raagani on page 162 of Adi Sri Guru Granth Sahib Ji.
When Sri Guru Amar Daas Ji was residing at his asthaan on the banks of Ganga, a Pandit came and questioned the Guru on the philosophy being preached. The Pandit asked the Guru if the teachings of Guru Nanak Dev Ji, written in Gurmukhi, were any different then the old Sanskrit texts, the Vedas etc, and if they are the same in philosophy, then why was there a need to preach if such texts already exist? Sri Guru Ji replied with the following verses:
ਮਹਲਾ ੩ ਗਉੜੀ ਬੈਰਾਗਣਿ ॥
ਜੈਸੀ ਧਰਤੀ ਊਪਰਿ ਮੇਘੁਲਾ ਬਰਸਤੁ ਹੈ ਕਿਆ ਧਰਤੀ ਮਧੇ ਪਾਣੀ ਨਾਹੀ ॥
The clouds pour their rain down upon the earth, but isn't there water within the earth as well?
ਜੈਸੇ ਧਰਤੀ ਮਧੇ ਪਾਣੀ ਪਰਗਾਸਿਆ ਬਿਨੁ ਪਗਾ ਵਰਸਤ ਫਿਰਾਹੀ ॥੧॥
Water is contained within the earth; without feet, the clouds run around and let down their rain.1
One thing to remember is that in Adi Guru Granth Sahib Ji it is clearly stated that the Vedas were from Akal Purkh and were given to Brahma [rather than created by him] to spread and propagate them for people to read and study:
ਚਾਰੇ ਵੇਦ ਬ੍ਰਹਮੇ ਕਉ ਦੀਏ ਪੜਿ ਪੜਿ ਕਰੇ ਵੀਚਾਰੀ ॥
(ਆਸਾ ਮਹਲਾ ੩ ਅਸਟਪਦੀਆ ਘਰ ੩, ਅੰਗ ੪੨੨)