Wathila bin Asqa, whose eyesight had failed, called me over and said, "Khabab, lead me to Yazid bin Aswad al-Jurashi." He then mentioned the narration, in which Yazid said, "Receive good news, for I heard the Messenger of Allah ﷺ say that Allah said, 'I am as My servant thinks of Me, so let him think of Me whatever he wishes.'"
حدثنا أبو المغيرة قال حدثنا هشام بن الغاز قال حدثني
دعاني واثلة بن الأسقع وقد ذهب بصره فقال يا خباب قدني إلى يزيد بن الأسود الجرشي فذكر الحديث فقال أبشر فإني سمعت رسول الله ﷺ يقول عن الله عز وجل أنا عند ظن عبدي بي فليظن بي ما شاء
Its isnad is sahih. Hisham bin Ghaz is Ibn Rabia Jurashi, and he is trustworthy and among the most excellent. Abu Nadr here is Salim bin Abu Umaya Madani, the trustworthy, firmly reliable, well-known narrator. The hadith was narrated by Darimi 2/395, no. 2731, and it has already appeared at 15958.