Where is the verse saying someone “will receive a crown upon his appearing”?

You may be thinking of

Blessed is the man who remains steadfast under trial, for when he has stood the test he will receive the crown of life, which God has promised to those who love him. (James 1:12)

or

Henceforth there is laid up for me the crown of righteousness, which the Lord, the righteous judge, will award to me on that Day, and not only to me but also to all who have loved his appearing. (2 Timothy 4:8)