All praise is surely due to Allah Most High. We praise Him, seek aid ONLY from Him, seek forgiveness ONLY from him and seek guidance from Him. We seek refuge in Allah from the evil within ourselves and the wicked among our deeds. Whoever Allah guides, none can lead astray and whoever Allah decrees to go astray, non can guide. I bear witness that there is no deity but Allah and I bear witness that Muhammad 
is his slave and messenger.
Allah has extolled the virtues of the Companions of the Prophet many places in the Qur’ân. A Companion is defined as one who met the Prophet in a state of belief and who died in that state. Allah said (after mentioning some of the hypocrites who stayed behind from Jihad): {Rather, the Prophet and those who believe with him fought with their property and their lives for these are all good things, they are the successful ones and Allah has prepared for them gardens beneath which rivers flow therein forever and that is the great success.} At-Taubah: 88-89
Allah’s praise of the Companions also extends to all those who follow their way. Allah said: {The forerunners those who came first among the Migrators and the Helpers and those who followed them with the best. Allah is pleased with them and they are pleased with Him and Allah has prepared for them gardens beneath which rivers flow therein forever and that is the great success.} At-Taubah: 100
The best generations of all time are: the generation of the Prophet i.e., the Companions (Sahâbah), those who followed them (at-taabi’een) and the ones who followed those (atbaa’ at-taabi’een). They are our best example. When we doubt whether a certain practice or belief is a prohibited Bid’ah or a valid interpretation and a good practice in the Deen, we simply have to look at these generations. If it is in the area of worship and they did not practice it or anything similar to it, or they openly condemned it then we know with certainty that it is not part of Islam and is the Bid’ah which Allah and His Prophet have absolutely forbidden.
The Prophet said: “The best of my nation is my generation then those who follow them and then those who follow them.” Saheeh Bukhari
The word for “generation” is qarn. Nowadays, this word is used to mean “century”. There are three interpretations of the word in this Ahaadeeth:
1. One hundred years. There are several Ahaadeeth narrated in which the Prophet said that someone will reach “qarn” and then other reports state that that person lived to 100 years. There are differences as to this last point, however.
2. The people of a particular time who were together in a certain affair – such as under a particular prophet or leader.
3. That the “qarn” of the Prophet is the Companions (Sahâbah), the next one is the Followers (taabi’een) and the third one is their Followers (atbaa’ at-taabi’een).
Notice that the last two are pretty similar. The third one is the best in terms of the meaning of this Ahaadeeth. So the generation of the Companions lasted until the last of them passed away and likewise the two generations after them.
“The scholars have agreed that the last of the those who followed those who followed lived to around 220 years. After that time, all sorts of innovations appeared and many of the deviant sects began. The Mu’tazilah spoke out loudly and widely and the philosophers raised their heads. The people of knowledge were tested by being forced to say that the Qur’ân was created. In short, things changed very drastically and things have remained deficient ever since. The Prophet’s statement that “…and then lies become widespread…“ was manifest very clearly and came to include statements, actions and beliefs. May Allah help us!”
In another version of this Ahaadeeth, the Prophet adds: “…then, after you are a people who bear witness without being asked to do so they betray and are not trusted they swear oaths and do not fulfill them and fatness will appear among them.“
The only protection for this Ummah is to stick to the way of the Companions and the first generations.
Abi Burda reports from his father: “We prayed Maghrib with Allah’s Messenger then we said: Why not sit until we pray Isha with him ? And so we sat and the Prophet came out to us and said: “Are you still here?“ We said: “O Allah’s Messenger we prayed Maghrib with you and we decided to sit here until we pray Isha with you.” He said: “You have done well.” Then, he raised his head toward the heavens – and he used to do that frequently – and said: “The stars are the protection for the sky – when the stars have gone, that which has been forewarned will come to the sky. I am the protection for my Companions – when I have gone, that which has been forewarned will come to my Companions. My Companions are the protection for this Ummah – when they have gone, that which has been forewarned will come to this Ummah.” (Muslim)
