فَهَذاso this بَديهٌspontaneous verse لاnot كَتَحبيرِlike the polished composition of قائِلٍa poet
فَهَذا بَديهٌ لا كَتَحبيرِ قائِلٍ
إِذاwhen ماemphatic particle أَرادَhe wishes القَولَthe verse زَوَّرَهُhe carefully crafts it شَهراfor a month
إِذا ما أَرادَ القَولَ زَوَّرَهُ شَهرا
So this is spontaneous verse, not like a poet’s polished composition,
So this is obvious, no need for a speaker's preparation,
who, when he wishes to compose, spends a month crafting it.
When he wants to say it, he can make it up for a month.
Sol 6.1