The Bridge [Crossing the Bridge of Siraat ]

Siraat in Arabic means a way or a road; according to traditions, it is a bridge or road which passes from the top of Hell. In a Hadith it is stated that Pul-e-Siraat is a bridge thinner than a hair, sharper than a sword and hotter than fire. In the Hereafter, true believers will pass over it quickly, some will find some difficulty crossing it but will eventually find relief, and others will slip and fall down in the pits of Hell. Shaikh Abbas Qummi mentions in Manazelul Akhera that the likeness of Pul-e-Siraat is of "The Right Path" (Siraat al-Mustaqim) of this world – the path of our Ahlul Bayt (peace be upon them); in Sura Fatiha, Siraat al-Mustaqim refers to both these paths: the path of the Ahlul Bayt and Pul-e-Siraat.
Not a single person will be able to escape from walking over this bridge – neither the people of Paradise, nor the people of Hell. Allah says in the Qur'an: "And there is not one of you but shall come to it, this is an unavoidable decree of your Lord. And we will deliver those who guarded (against evil), and we will leave the unjust therein on their knees." (19:71-72) Narrated from the Holy Prophet (peace be upon him and his progeny), this bridge contains seven Passes (Aqabat). There will be stations in each Pass and each station will be 70 Farsakh (1 Farsakh = 5.5 km) long, and 70,000 Angels will be posted at each Pass.
Those who safely pass through all seven Passes will arrive at the Abode of Permanence (Dar al-Baqa), where they will live an everlasting life without any troubles. They will reside in the neighborhood of Allah with the Prophets and the Imams (peace be upon them all), the martyrs and the righteous ones from among His slaves. However, if a person is stopped at a Pass, and neither a good deed of his nor the Mercy of Allah reaches him, he will stumble in his step and be hurled down in the fire of Hell. (E'teqadat al-Imamiyah)

First Pass: Kindness, Trust and Love of the Ahlul Bayt

The first station here is of maintaining womb relations (Silat al-Rahm): it is the first place we will be halted on this bridge. The person who in this world is not merciful towards his parents and relatives will have a short life, will not prosper, will be halted on the first station on Pul-e-Siraat in the Hereafter and no mercy will be shown towards him. Allah warns us in the Holy Qur'an: "And be careful of your duty to Allah, by whom you demand one of another (your rights), and to the ties of relationship" (4:1). Indeed, it is a virtue that has been repeatedly emphasized to us through numerous traditions, as it is one that achieves the pleasure of Allah, averts many adversities and increases one's Rizq (sustenance) and lifespan. Visiting our relatives when they fall sick, helping them when they are in need, fulfilling their wants and visiting them on important days such as Eid all fall under Silat al-Rahm.
The second station on this Pass is of trust (Amanah) – whether it is the wealth or item that someone has entrusted you with, or the secret you have been entrusted to protect. Similarly, if something has been borrowed and not returned before the given period of time, it will be deemed a violation of trust. It has been narrated that none of a person's deeds will be of any help to him when he walks over Pul-e-Siraat if he has committed a breach of trust or severed relations with his relatives; he will fall flat into the pits of Hell.
The third station is the love of the Ahlul Bayt (Wilayah). Many traditions have been quoted in both Shia and Sunni books to explain that Wilayah means the Love of Imam Ali (peace be upon him). Allama Huwainee and Tabari, both great scholars of the Ahlul Sunnah, quote the Holy Prophet as saying: "O Ali! Whoever denies your love will be stopped (from going further) over Pul-e-Siraat." The love of Ali is surely the key to pass easily over this frightful bridge.

Source : http://islamicinsights.com/religion/religion/crossing-the-bridge-of-siraat.html