Question: 

Is it lawful to pray Salah on a bed?

Answer: 

If the individual prays on a bed and it’s material is such that the individual’s forehead can push down to some extent on the bed then it is unlawful. These days’ mattresses are not ideal for prayer.

And Allah ﷻ knows the best

Imam Ahmad Rida Khan رحمة الله تعالى عليه

Translation by Dr Musharraf Hussain Al-Azhari Translator of Majestic Quran, www.majesticquran.co.uk