Sunan Abu Dawud
1811
Sahih+2

Narrated Abdullah ibn Abbas: The Prophet (ﷺ) heard a man say: Labbayk (always ready to obey) on behalf of Shubrumah. He asked: Who is Shubrumah? He replied: A brother or relative of mine. He asked: Have you performed hajj on your own behalf? He said: No. He said: perform hajj on your own behalf, then perform it on behalf of Shubrumah

SahihAl-Albani
SahihMuhammad Muhyi Al-Din Abdul Hamid