Muwatta Malik 260
موطأ مالك#260SahihThese are the words of a Companion, not of the Prophet ﷺ. The chain is graded on its own terms.
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَقُولُ صَلاَةُ اللَّيْلِ وَالنَّهَارِ مَثْنَى مَثْنَى يُسَلِّمُ مِنْ كُلِّ رَكْعَتَيْنِ .
Yahya related to me from Malik that he had heard that Abdullah ibn Umar used to say, "(Voluntary) prayer in both the day and night is two at a time with a taslim after every 2 raka'ahs." Malik said, "That is the custom among us
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 7:7