Sunan Ibn Majah
1154
Sahih+2

It was narrated that Qais bin ‘Amr said:“The Prophet (ﷺ) saw a man praying two Rak’ah after the Subh prayer and said, ‘Is the Subh prayer to be offered twice?’ The man said to him: ‘I did not pray the two Rak’ah before it, so I prayed them (now).’ The Messenger of Allah (ﷺ) remained silent.”

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi