What is the reward for Iʿtikāf?

I'tikaf is a legitimate act of worship, and the general hadiths encouraging supererogatory acts of worship indicate its virtue, such as Allah's statement in the Hadith Qudsi: "My servant does not draw near to Me with anything more beloved to Me than what I have enjoined upon him, and My servant continues to draw near to Me with supererogatory acts until I love him." As for the hadiths specifically about the virtue and reward of I'tikaf, all of them are weak or fabricated. Abu Dawud reported that Imam Ahmad said he knew nothing about the virtue of I'tikaf except something weak. Among these weak hadiths are: the hadith, "He confines sins, and good deeds are recorded for him like all good deeds for one who performs good deeds," and the hadith, "Whoever observes I'tikaf for one day seeking the Face of Allah, Allah will place three trenches between him and the Fire," and the hadith, "Whoever observes I'tikaf with faith and hope for reward, his past sins will be forgiven," and the hadith, "Whoever observes I'tikaf for ten days in Ramadan, it is like two Hajj and two 'Umrah."