Quoted by Sh Al-Albaanee in SilsilatulaḥadīthusṢaḥīhah No. 134 reported by al-Bukhaari in al-Adab al-Mufrad and by Aḥmad which is ṣaḥīḥ from the ḥadīth of ‘Abdullāh ibn Amr who said that the Prophet sallAllaahu ‘alaihiwasallam said:
“Indeed the Prophet of Allaah, Nooh sallAllaahu ‘alaihiwasallam when death came to him, he said to his son, ‘I will tell you a final admonition (or a will). I command you with two things, and I forbid you from two things. I command you with Laa ilaaha illAllaah because the seven heavens and the seven earths if they are placed on one scale (of a balance) and Laa ilaaha illAllaah was placed on one scale then Laa ilaaha illAllaah would outweigh them. And if the seven heavens and the seven earths were a closed ring it would be broken open by Laa ilaaha illAllaah. And SubhaanAllaah wabihamdihi is the prayer of everything and due to these two the creation are given sustenance. And I forbid you from shirk and from pride ...' "
(transcribed from the explanation of Kitaab-ut-Tawḥīd available on salafiaudio.com)
These narrations remind me of the ḥadīth of the man who will come on the Day of Judgment with scrolls of sins, but then a small card/paper with "Laa ilaaha illAllaah" written on it will be placed on his Scale and that card will outweigh the recorded sins.
Can someone post the text/reference of that ḥadīth?
I happened to come across the ḥadīth in the endnotes of As-Sa'di's explanation of Kitaab at-Tawḥīd translated by Abū Khaliyl:
From 'Abdullāh bin 'Amr bin al-'Aas that Allaah's Messenger, ṣallallāhu 'alayhi wa sallam said:
"On the Day of Resurrection, Allaah will distinguish a man from my ummah before all creation. Ninety-nine scrolls will be unrolled before him, each scroll reaching as far as can be seen. Then it will be said, 'Do you deny any of this? Have My recorders wronged you?' He will reply, 'No my Lord!' So he will be asked, 'Do you have any excuse?' He replies, 'No my Lord!' Then He says. 'There is for you a good deed with Us, you will certainly not be wronged today.' Then a card will be brought out in it is "Ashhadu anlaa ilaaha illAllaa, wa ashhadu anna Muhammadan 'abduhu wa rasooluh." So He says, 'Bring your scale.' The man says, 'What is this card compared to these scrolls?' He will say 'You will not be wronged.' So the scrolls will be placed in one pan of the scale, and the card in the other, so the scrolls become light and the card becomes heavy. Nothing outweighs the name of Allaah."
(Recorded by Aḥmad, Tirmidhi, and others, see al-Ṣaḥīhah no.135)