Man’s deeds control the means of passing over the Siraat
8-3-2012 | IslamWeb
Question:
Is it an act of polytheism to say: ” nothing but your deeds will save you from the Siraat (Bridge over Hell)”?
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad 
is His slave and Messenger.
This saying is not considered a polytheistic one. It is reported in the Sunnah (Prophetic tradition) that people will vary in their status when crossing the Siraat in accordance with their deeds: some will pass as quick as lightning, some as quick as wind, some as swift as birds, some as quick as the fastest animals, some will pass quickly and some will pass it walking. Some will pass creeping on their bellies and will ask Allaah The Almighty about the reason for this. He will tell them that it is because of their deeds in this worldly life that lead them to this state. [Al-Haakim and Ath-Thahabi: Saheeh]
You need to know that good deeds are just reasons for salvation, they do not save man by themselves. Salvation is only obtained through the Mercy of Allaah The Almighty, who guides man towards good deeds and accepts them from him. On the authority of Abu Hurayrah 
the Prophet, sallallaahu ‘alayhi wasallam, stated that no one will be saved from torture by his deeds, even himself, sallallaahu ‘alayhi wa sallam. It is only the Mercy of Allaah The Almighty that saves whoever Allaah The Almighty wants. [Muslim].
An-Nawawi 
also explained that there is no contradiction between this Hadeeth and the verses (that mean):
• {Enter Paradise for what you used to do.} [Quran 16:32].
• {And that is Paradise which you are made to inherit for what you used to do.} [Quran 43:72].
There is no contradiction because the verses mean that entering Paradise is because of deeds, whereas guiding man to these deeds and accepting them come only from the mercy of Allaah The Almighty. Therefore, man does not enter Paradise just because he did these deeds (and this is meaning of the Hadeeth); rather he enters it as a result of doing the deeds, the guidance to do them and their acceptance, which are all from the mercy of Allaah The Almighty.
Allaah Knows best.