God of all is one, there is no second. Recognize the human race as one. - Guru Gobind Singh

Maanas Ki Jaat Sabai Ekai Pehachaanbo - Recognize the human race as one.  - Guru Gobind Singh
A translation of this of this poem:

ਕੋਊ ਭਇਓ ਮੁੰਡੀਆ ਸੰਨਿਆਸੀ ਕੋਊ ਜੋਗੀ ਭਇਓ ਕੋਊ ਬ੍ਰਹਮਚਾਰੀ ਕੋਊ ਜਤੀ ਅਨੁਮਾਨਬੋ ॥
कोऊ भइओ मुंडीआ संनिआसी कोऊ जोगी भइओ कोऊ ब्रहमचारी कोऊ जती अनुमानबो ॥
Somebody became a Bairagi (recluse), somebody a Sannyasi (mendicant). Somebody a Yogi, somebody a Brahmchari (student observing celibacy) and someone is considered a celibate.

ਹਿੰਦੂ ਤੁਰਕ ਕੋਊ ਰਾਫਜੀ ਇਮਾਮ ਸਾਫੀ ਮਾਨਸ ਕੀ ਜਾਤਿ ਸਬੈ ਏਕੈ ਪਹਿਚਾਨਬੋ ॥
हिंदू तुरक कोऊ राफजी इमाम साफी मानस की जाति सबै एकै पहिचानबो ॥
Someone is Hindu and someone a Muslim, then someone is Shia, and someone a Sunni, but all the human beings are recognized as one and the same.

ਕਰਤਾ ਕਰੀਮ ਸੋਈ ਰਾਜਕ ਰਹੀਮ ਓਈ ਦੂਸਰੋ ਨ ਭੇਦ ਕੋਈ ਭੂਲਿ ਭ੍ਰਮ ਮਾਨਬੋ ॥
करता करीम सोई राजक रहीम ओई दूसरो न भेद कोई भूलि भ्रम मानबो ॥
Karta (The Creator) and Karim (Merciful) is the same Lord, Razak (The Sustainer) and Rahim (Compassionate) is the same Lord, there is no other second, therefore consider this verbal distinguishing feature of Hindusim and Islam as an error and an illusion.

ਏਕ ਹੀ ਕੀ ਸੇਵ ਸਭ ਹੀ ਕੋ ਗੁਰਦੇਵ ਏਕ ਏਕ ਹੀ ਸਰੂਪ ਸਬੈ ਏਕੈ ਜੋਤ ਜਾਨਬੋ ॥੧੫॥੮੫॥
एक ही की सेव सभ ही को गुरदेव एक एक ही सरूप सबै एकै जोत जानबो ॥१५॥८५॥
Thus worship the ONE LORD, who is the common enlightener of all; all have the same beautiful image, and all come from the same ONE LIGHT. 15.85.

- Guru Gobind Singh, Dasam Granth