Abu Dawud

Hadith Commentary:
(1)
If, at the time of sleeping, a fire is left burning in the house and it is not extinguished, nor is any arrangement made to ensure safety from it, then sometimes, due to its flaring up, great loss of life and property can occur.
Hafiz Ibn Hajar rahimahullah writes that if there is a single person in the house, he should extinguish the fire before sleeping or make a reasonable arrangement to ensure safety from it. And if there are several people in the house, then the last person to remain awake in the house must fulfill this responsibility.
(Fath al-Bari: 11/103) (2)
The same applies to electricity; it should also be turned off before sleeping, otherwise there is a risk of great loss.
And Allah knows best.

Benefits and Issues:

➊ Leaving a burning candle or lamp unattended while sleeping poses a risk of accident. Something in the house could catch fire.

➋ In winter, sometimes a coal brazier is used to heat rooms. Leaving a brazier burning in a closed room while sleeping not only poses a fire hazard, but the accumulation of poisonous gas in the room can also prove fatal. Leaving a gas heater on while sleeping also carries great dangers. The harms of this are frequently reported in newspapers.

➌ If an electric bulb is left on, there is no such danger; however, it is difficult to get restful sleep in bright light. If necessary, only a very dim light bulb should be used.

➍ It is obligatory to take necessary precautionary measures when using any dangerous item (such as electrical appliances).

Benefit:
From this hadith, it is understood that one should extinguish every kind of fire before sleeping, even if there is no apparent danger, because an issue can arise at any time.