dhiya nigrhyamano ’pi
bhruvor madhyat prajapateh
sadyo ’jayata tan-manyuh
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Although he tried to curb his anger, it came out from between his eyebrows, and a child mixed blue and red was immediately generated.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The face of anger is the same whether exhibited due to ignorance or knowledge. Although Brahma tried to curb his anger, he could not do so, even though he is the supreme being. Such anger in its true color came from between the eyebrows of Brahma as Rudra, in a mixed color of blue (ignorance) and red (passion), because anger is the product of passion and ignorance.