The expression is rooted in ancient Turkic traditions where warriors swore on their weapons. Holding the hilt of a sword, they would declare that if they broke their word, the blue steel of the blade (associated with the "sky" or "Gök") should pierce them and come out stained with their blood (red/“kızıl”).
GRUP GÖKTÜRKLER /Bilge Kağan Kara/Gök Girsin Kızıl Çıksın. - YouTube. Grup Gokturkler Gok Girsin Kizil Ciksin
GRUP GÖKTÜRKLER /Bilge Kağan Kara/Gök Girsin Kızıl Çıksın. The expression is rooted in ancient Turkic traditions
"Gök Girsin Kızıl Çıksın" is a traditional Turkish warrior's oath and patriotic anthem performed by the musical group . The phrase translates to "May [the sword] enter like the sky and exit red [with blood]," symbolizing a sacred vow of loyalty where the oath-taker invites death if they ever betray their people, heritage, or principles. Historical Significance - YouTube
What is the meaning of ""gök girsin, kızıl çıksın""? - HiNative