Umar said to Saad, "People have complained about you in everything, even in your prayer."Saad replied, "As for me, I prolong the first two rakahs and shorten the last two, and I spare no effort in following the prayer of the Messenger of Allah ﷺ."Umar said, "You have spoken the truth. That is what I thought of you," or "that was my opinion of you."
قال عمر لسعد: لقد شكوك في كل شيء حتى في الصلاة. قال: أما أنا فأمد في الأوليين، وأحذف في الأخريين. ولا ألو ما اقتديت به من صلاة رسول الله ﷺ. قال: صدقت. ذاك الظن بك، أو ظني بك.
Bukhari reported it in adhan (770) and Muslim in prayer (159/453), both from the hadith of Shubah, from Abu Awn, who said, "I heard Jabir bin Samura," and he mentioned it. This hadith contains a story that was mentioned earlier in the chapter on recitation in Fajr, Dhuhr, and Asr. That took place during the "Isha prayer".