Bukhari 770

Narrated Jabir bin Samura:`Umar said to Sa`d, "The people complained against you in everything, even in prayer." Sa`d replied, "Really I used to prolong the first two rak`at and shorten the last two and I will never shorten the prayer in which I follow Allah's Messenger (ﷺ)." `Umar said, "You are telling the truth and that is what I think about you