Descend down (the stairs) - это масло масляное. Descend - это уже спускаться/снижаться. Down здесь неуместно. Посмотрите в словарях, Ефим.

хватить наводить тень на плетень и показывать свою глупость

можно и спускаться с небес по вашу душу

Yefim, you should think before saying something like that. Shame on you!

Insulting other people won't make you look better.

Yefim, please stop embarrassing yourself. Your English is shitty and you don't have enough guts to admit it. But believe me, people who have better knowledge can see your lack of grammar and common sense. Your reaction to my absolutely peaceful posts is totally ridiculous. Stop being an ignorant prick and start learning from people.
Now back to the topic. Check out the dictionaries. Go through the examples, EVERY link has a "descending the stairs" example and a friggin explanation what exactly this verb means. Read and learn:
https://www.collinsdictionary.com/dictionary/english/descend
http://dictionary.cambridge.org/dictionary/english/descend
http://www.macmillandictionary.com/dictionary/british/descend
https://en.oxforddictionaries.com/definition/descend

Aleh La, dear, believe me I couldn't care less about Yefim's "insults" :)

пошли вы........