Muwatta Malik 535
موطأ مالك#535SahihThese are the words of a Successor — the generation after the Companions — not of the Prophet ﷺ.
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ سَأَلَ ابْنَ شِهَابٍ عَنِ الرَّجُلِ، يُدْرِكُ بَعْضَ التَّكْبِيرِ عَلَى الْجَنَازَةِ وَيَفُوتُهُ بَعْضُهُ فَقَالَ يَقْضِي مَا فَاتَهُ مِنْ ذَلِكَ .
Yahya related to me that Malik asked Ibn Shihab about a man who caught some of the takbirs said over the corpse and missed the rest, and Ibn Shihab said, "He completes what he has missed
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:
Salim al-HilaliMaqtu Sahih
In-book reference: 16:16