It is narrated from Sayyiduna Sa'id bin al-Musayyib (may Allah have mercy on him) that Sayyiduna Abu Bakr (may Allah be pleased with him) and Sayyiduna Umar (may Allah be pleased with him) mentioned to the Messenger of Allah (ﷺ) the way each of them performed Witr. Sayyiduna Abu Bakr (may Allah be pleased with him) said, "I perform Witr in the early part of the night." Sayyiduna Umar (may Allah be pleased with him) said, "I perform Witr in the last part of the night." So the Prophet (ﷺ) warned Sayyiduna Abu Bakr (may Allah be pleased with him) and approved Sayyiduna Umar (may Allah be pleased with him).
Hadith Referenceالسنن المأثورة / باب من أوتر من أول الليل وآخره / 171
Hadith Takhrijمصنف عبدالرزاق : 14/3، رقم : 4615، مصنف ابن ابي شيبة : 282/2 مرسل رجاله ثقات صحیح