Narrated Abu Hurairah: The Messenger of Allah ﷺ as saying: When one of you gets up at night, he should begin the prayer with two short rak'ahs.
Hadith Referenceسنن ابي داود / أبواب قيام الليل / 1323
Hadith Gradingالألبانی:ضعيف والصحيح وقفه | زبیر علی زئی:صحيح مسلم (768)
Hadith Takhrij« تفرد بہ ابوداود، (تحفة الأشراف: 14572)، وقد أخرجہ: صحیح مسلم/المسافرین 26 (768)، مسند احمد (2/232، 279، 399) (صحیح) » (آگے کے ابوداود کے تبصرہ سے اندازہ ہوتا ہے کہ مرفوع قولی کی جگہ ابو ہریرہ رضی اللہ عنہ پر وقف زیادہ صحیح ہے، نیز صحیح مسلم وغیرہ میں رسول صلی اللہ علیہ وسلم کے فعل سے یہ صحیح ہے، ملاحظہ ہو: ضعیف ابی داود: 2؍ 59- 60)
1؎ : Most likely, what is meant by this is the "greeting of ablution" (tahiyyat al-wudu), that is, first he should perform these two units (rak‘ahs), then begin the tahajjud prayer; or it refers to the tahajjud prayer itself, but that its beginning should be with a light (short) prayer. In another narration it is stated «ثم ليطول بعد ما شاء» meaning, after that he may lengthen (the prayer) as much as he wishes.
Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates: The Noble Prophet (peace and blessings be upon him) said: "When a person wakes up at night, he should perform two short rak‘ahs with which he should begin his prayer."
Shaykh Muhammad Ibrahim bin Basheer
Benefit: The first two units (rak‘ahs) of the Tahajjud prayer should be performed lightly; this applies to certain occasions, and at other times the Prophet sallallahu alayhi wa sallam would perform the first two units of Tahajjud for a longer duration. [صحيح مسلم : 763، 1792]
Source: Musnad al-Humaydi: Commentary by Muhammad Ibrahim bin Bashir, Page: 1014