Ash-Shaykh Muhammad bin Saalih al-Uthaymeen, rahimahullah, said :

… وضع الرجلين في حال القيام طبيعي بمعنى أنه لا يلصق بعضهما ببعض، ولا يباعد ما بينهما، كما روي ذلك عن ابن عمر – رضي الله عنهما – ذكره في شرح السنة “أنه كان رضي الله عنه لا يباعد بين رجليه ولا يقارب بينهما” هذا في حال القيام، وفي حال الركوع، أما في حال الجلوس:

The position of the two legs when standing is the natural way, meaning that he shouldn’t join them together nor should he make them distant from one another , as been narrated on Ibn Umar, may Allah pleased with him of what was mentioned in the book ‘Sharhu Sunnah’ that he, may Allah pleased with him, wouldn’t make his legs distant from one another nor would he draw them near to one another. This is in relation to when standing and when bowing…

… وأما في حال السجود فمن الأفضل أن يلصق إحدى القدمين بالأخرى، وأن لا يفرق بينهم

And as for the case of prostration then what is preferred is that he connects each foot to the other and he shouldn’t separate between them.

[Reference]

Translated by

AbdulFattaah bin Uthman
Abu Fajr