keep your eyes on the prize

"Talk like TED" (Carmine Gallo著)を読み始めました。TEDは以前NHKの教育TVで何回か見た事があり、興味を覚えたプリゼンターの本（ZOOBIQUITY など）を読んだこともあります。最近は見ていませんが番組はまだ続いているのでしょうか？
"Talk like TED" から取り上げる最初の表現は "keep your eyes on the prize" です。
And during the break there was a deputy sheriff who was offended that the janitor had come into court. And this deputy jumped up and he ran over to this older black man. He said, "Jimmy, what are you doing in this courtroom?" And this older black man stood up and he looked at that deputy and he looked at me and he said, "I came into this courtroom to tell this young man, keep your eyes on the prize, hold on."

"keep your eyes on the prize" は慣用句の様に見えますが、慣用句として取り上げている辞書は見当たりません。Webで検索すると説明がありました。幾つかのサイトから説明を引用します。
・Word Associations Network: KEEP ONE'S EYES ON THE PRIZE, verb. To be eagerly focused on succeeding
・10 Useful Business English expressions: In order to maintain your focus, it is necessary to keep in mind why you have set up a business and why you have been trying to carve out a niche in this difficult industry. Have a goal in mind or keep an eye on the prize.

・Writing Explained: To remain steadfastly focused on one’s goal.
Origin: This expression likely became popularized by a song of the same name during the Civil Rights Movement in America. Many African Americans, and others involved in the movement, used this song as a way to motivate and unite those in the fight for equal rights.
なるほど、公民権運動でよく歌われた歌から広まった表現なのですね。ここでは紹介しませんが、元歌があり、それはゴスペルソングの様です。