The Messenger of Allah ﷺ said, "The best testimony is the one given by its bearer before he is even asked for it."
حدثنا إسماعيل قال حدثنا عبد الرحمن بن إسحاق عن محمد بن أبي بكر بن حزم عن أبيه عن عبد الرحمن بن عمرو بن عثمان
قال رسول الله ﷺ خير الشهادة من شهد بها صاحبها قبل أن يسألها
Its isnad is sahih. All of its narrators have been mentioned before, and they are well-known and reliable. The hadith was previously mentioned at 16977.