«اخرج فناد في الناس: من شهد أن لا إله إلا الله وجبت له الجنة» .
(صحيح) … [ع] 3 عن أبي بكرة. الصحيحة 1135)
It is reported that the Messenger of Allah (peace and blessings of Allaah be upon him) said:
“Go out and proclaim among people: for the one who testifies that there is no deity worthy of worship, except Allah, paradise will become obligatory.”
This hadith was narrated by Abu Ya’la 105, according to Abu Bakra, may Allah be pleased with him.
Sheikh al-Albani called the hadith authentic. See Saheeh al-Jami ‘as-saghir 229.