Guru Nanak Dev Ji shows such a Gareebi (humility) in Jap Ji Sahib (First Sikh prayer recited daily). You read it every day though you may not have noticed this. There are three Asankh (many types of people) Pauria (stanzas) in Japji Sahib. Guru Nanak Dev Ji doesn’t include their name in the Asankh Jap stanza, referring to all types of spiritual people in this world. But, amazingly, their name appears in the Asankh Moorakh stanza, referring to all different kinds of sinners in the world. In this stanza, the true king (Guru Nanak Dev Ji) says that I am a fool. In such subtle ways, Guru Ji shows immense Gareebi.
To learn more on this topic, watch the video by Bhai Harman Singh