The Messenger of Allah ﷺ said, "Paradise is closer to any one of you than the strap of his sandal, and the Fire is just as close."
حدثنا ابن نمير عن الأعمش عن شقيق
قال رسول الله ﷺ الجنة أقرب إلى أحدكم من شراك نعله والنار مثل ذلك
Its isnad is sahih. Bukhari related it, 11:275, through the route of Mansur and Amash, from Abu Waail, who is Shaqiq.