Is it authentic from ‘Umar may Allāh be pleased with him that he used to elongate the du’ā in Tahajjud?
Do you mean du’ā of qunūt or du’ā of sujūd?
As for the sujūd then the Prophet ﷺ used to elongate in sujūd and other than him.
Ā’ishah may Allāh be pleased with her said:
صلى أربعا لا تسأل عن حسنهن وطولهن، ثم صلى صلى أربعا لا تسأل عن حسنهن وطولهن، ثم صلى ثلاثاً.
“The Prophet ﷺ prayed four units, don’t ask about their length and quality, then he prayed another four units, don’t ask about their length and quality, then he prayed three units.”
So she is describing the length and quality, and they used to take from him concerning these Sunan.
Or do you intend that he elongating in the du’ā of qunūt. It is authentic from him that he uses to make du’ā against the disbelievers in the qunūt of Ramadhān especially in the latter part of it. He used to increase in du’ā against the disbelievers, cursing them.
Answered by: Shaykh, the Allamah, the Trustworthy Advisor, Abu Abdirrahman Yahya bin Ali Al-Hajuri – may Allah preserve him
Translated by: Abū ‘Abdillāh ‘Omar bin Yahya Al-‘Akawi