Mufti Aḥmad Yār Khān NaꜤīmī رَحْمَةُ الـلّٰـهِ عَـلَيْه explains this hadith as follows:

This does not mean Allah enters or “possesses” a saint. The way fire is found in coal, or colour and fragrance is found in flowers; this is referred to as ḥulūl. Allah is free from doing this, and believing He does this is disbelief.  

This hadith has many meanings. One of them entails these limbs of the saint no longer committing sin and being used only in good actions. Worship becomes easy for them, as Allah Himself causes them to do it.

Another meaning is the saint does not use his limbs for the world, but only for Allah instead. He remembers Allah wherever he looks and with whatever he hears.

Or it means this person becomes فَنافِی اﷲ. As a result of this, Allah grants power to do things which cannot be understood by human intellect.  

This is evidenced by Prophet YaꜤqūb عَـلَيْـهِ الـسَّـلاَم being in Canaan, and smelling the fragrance of Prophet Yūsuf’s shirt, which was in Egypt. Prophet Sulaymān عَـلَيْـهِ الـسَّـلاَم heard the voice of an ant at 3 miles distance. Āṣif b. Barkhiyā brought the throne of Bilqīs from Yemen to Syria faster than an eye can blink. Sayyiduna ꜤUmar, whilst delivering a sermon, was able to make his voice reach Iran’s city of Nahavand whilst being in Madina.  

The Messenger of Allah صَلَّى اللهُ عَلَيْهِ وَاٰلِهٖ وَسَلَّم physically witnessed all that will take place until the Day of Judgement. These are all amazing manifestations of this divinely conferred power.^[1]

Dear Islamic brothers! We should try our best to perform nafl deeds,