The night after the attempt at “Sunday Morning” (which would not end up making the album) Mr. Harrell was back at Record Plant with Mr. Bieber. Again the singer was distracted; at midnight it would be his birthday. “I’m gonna get my Black Card,” he sang, “Order it tomorrow-oh-oh.”

He was working on “Believe,” the title track. An elegant, yearning love song about loyalty and trust, “Believe” could be about a family member, a girlfriend, or really, millions of fans. Mr. Bieber went into the booth to work on the swelling portion of the song.

“Just look at me nowwww,” Mr. Bieber sang.

Mr. Harrell said, “Oooooo, put that passion on it,” his face scrunched slightly as if a light odor had just hit his nose, a sign of approbation. “Try to catch that mmmmmmm.”

Mr. Bieber took the note: “Just look at mmmeee now.”

Mr. Bieber soon shifted to work on the song’s soaring hook, squeezing power from his light voice: “I don’t know how I got here/I knew it wouldn’t be easy/Doesn’t matter how many times I got knocked on the floor.”

Mr. Harrell shouted: ““I love it. I love that soft tone too.”

Mr. Bieber called back, “Do it again?”

“Absolutely,” Mr. Harrell said. “You killin’ it. I just need to understand you just a little bit more.”

Mr. Bieber tried again. “I don’t know how I got heeeerrrre/ I knew it wouldn’t be eeeeasyyyy,” he sang, hitting the last word of each line with more power and tang.

“Wooooooo!” Mr. Harrell exulted. “That’s incredible.”

Mr. Bieber came out of the booth to hear his vocals played back. “I’m so excited for my birthday, I can hardly even concentrate,” he said.

“But you’re killin’ it though,” Mr. Harrell replied. And with that Mr. Bieber went back into the booth.