ENOfficial
Narrated Zaid bin Khaled al-Juhani (RA): The Prophet (ﷺ) said, "Shall I not inform you who is the best witness? He is the one who produces his testimony before he is asked for it." .
Source: sunnah.com
Other translations
Arabic
عَنْ زَيْدِ بْنِ خَالِدٍ اَلْجُهَنِيِّ - رضى الله عنه - أَنَّ اَلنَّبِيَّ - صلى الله عليه وسلم -قَالَ: { "أَلَا أُخْبِرُكُمْ بِخَيْرِ اَلشُّهَدَاءِ? اَلَّذِي يَأْتِي بِشَهَادَتِهِ قَبْلَ أَنْ يُسْأَلَهَا" } رَوَاهُ مُسْلِم ٌ 1 .
sunnah.com