I have heard this colloquially but I would like to be pointed to a reference in the Hadith for the notion that "every spot that we do Sajdah at on this Earth, will testify for us on the Day of Judgment; it will emit light on that Day for us"
Islam Stack Exchange is a question and answer site for Muslims, experts in Islam, and those interested in learning more about Islam. It only takes a minute to sign up.Sign up to join this community
I could not find a hadith with those exact words, but this is inferred in later texts. Also, there is a supporting hadith .
Ar-Ramli said in Nihaayat al-Muhtaaj (1/552): It is Sunnah to move in order to offer a naafil or obligatory prayer from the place where one offered an obligatory or naafil prayer, so as to increase the number of places where one prostrates, for they will testify in one’s favour, and because that means filling more spots with worship. And if one does not move to another spot, then one should separate the prayers by speaking to someone. 
 I could not find a hadith with those exact words, but this is inferred in later texts. Also, there is a supporting hadith .
The statement that "every spot where we do sajdah will testify for us on the Day of Judgment" is not explicitly mentioned in the Quran or in any specific hadith (sayings of the Prophet Muhammad, peace be upon him), but it is a well-known and widely accepted Islamic belief.
The belief is based on the general Islamic teachings that emphasize the importance of prayer (salah) and the physical act of prostration (sujud) during prayer. The Quran mentions the prostration as a form of worship and submission to God in several verses, such as:
"So, prostrate to Allah and worship [Him]." (Quran 53:62)
"And they fall upon their faces weeping, and the Quran increases them in humble submission." (Quran 17:109)
The act of prostration is seen as a sign of humility, gratitude, and reverence towards God, and it is believed that every time a person performs sujud, they are demonstrating their faith and devotion to God.
The idea that every spot where a person performs sujud will testify for them on the Day of Judgment is based on the belief that these acts of worship leave a spiritual imprint on the physical world. According to Islamic tradition, even the earth and the rocks have the ability to bear witness to the good deeds of believers. This concept is mentioned in several hadiths, such as:
"The earth will testify for anyone who recites the Quran on it." (Tirmidhi)
"Verily, stones and earth will bear witness for me on the Day of Resurrection." (Bukhari)
Therefore, while the specific statement that "every spot where we do sujud will testify for us on the Day of Judgment" may not have a direct source in Islamic scripture or tradition, it is based on the general Islamic teachings on the importance of prayer and the belief that our actions leave a spiritual impact on the world around us.