神(God)なのに、英語にすると悪魔(Devil)になります。
In English, God becomes the Devil.
おそらく、『細部を甘く見ると、痛い目に遭うよ!』というニュアンスが理由。
This is probably because the nuance is more like "If you underestimate the importance of details, you're asking for trouble!"
細部の中に悪魔が掛けそうな祟りが待っていますので、中途半端はダメです。
It's like a devil's curse is hiding in the details, so you can't half-ass it.
しっかり細部を細かく復習し、小さなミスを一々退治しなきゃ。
Better to review those details carefully and eliminate each and every mistake.