There are also a number of works of early Islamic scholars available on the net.

 An excerpt from Imam al-Ghazali’s Ihya’ ‘Ulum al-Din (Revival of the Religious Sciences)

Another early scholar Imam Ibn Taymiyyah

 Imam Nawai is another famous early Islamic Scholar. See An-Nawawi's Forty Hadith .  

The early islamic scholar Ibn Hajar al-‘Asqalani

The Sahabah

The Prophet  (peace and
 blessings of Allaah be upon him) said in a saheeh hadeeth: "The best of mankind are my generation (or my century), then those who come after them, then those who come after them. Then there will come a people who will not care if their testimony comes before
 their oath or vice versa (i.e., they will not take such matter seriously)." (Reported by al-Bukhaari, Muslim and al-Tirmidhi)