expression, noun
ray of hope; glimmer of hope
A metaphorical expression for a small sign or source of hope in a difficult situation.
彼の言葉が私にとって希望の光となった。
His words became a ray of hope for me.
この新薬は患者たちに希望の光をもたらした。
This new medicine brought a glimmer of hope to the patients.
Compound of 希望 (hope) + の (possessive particle) + 光 (light). The metaphorical use is straightforward and modern.