"And applying Tajweed is an issue of absolute necessity, whoever doesn't apply Tajweed to Quran, then a sinner is he" (Muhammad nib Al-Jazaree, Quran and Hadeeth scholar of the 9th century)
A good friend of mine convinced me to take a Tajweed class with her recently, and although I have only been in attendance for only 3 weeks now, I have benefited greatly already. I pray that my learning this knowledge becomes sadaqah jariyah for her inshaa Allah. Anyway, after I read that quote I knew I had to be enrolled in this class! Imagine you spend your whole life reading the Quran, and later finding out its worthless in the sight of Allah (SWT), because you neglected to learn the proper recitation of the letters?! Crazy isn't it? The Quran has a right over all Muslims and a portion of that right is to recite it in accordance to how it was revealed.
Here are a few ahadiths that I found regarding the importance of reciting the Quran with Tajweed:
1) Prophet Muhammad (SAW) said "The one who has the one of the finest voice from among the people when reciting the Quran, is one whom you think fears Allah when you hear him recite"
2)Once when the Prophet (SAW) complimented Abu Moosaa al-Ash’ari on the beauty of his recitation, Abu Moosaa said " Had I known you were there, I would have made my voice more pleasant and emotional for you (Bukhari, Muslim)
3)Umm Salamah was asked about the recitation of the Prophet (SAW) and she described it as a recitation 'clearly distinguished letter by letter (Tirmidhi).
And the Quran: 'And recite the Quran (aloud) in a (slow and melodious) style (tarteela)' (Surah Muzzammil, Ayah 4)
Ali ibn Abi Talib (RA) said in the explanation of this aayah: “at-Tarteel is Tajweed of the letters and knowing where to stop (correctly)”.
Let us remember, that the Quran is the word of Allah where we find warnings, glad-tidings, parables, stories of the past, commands and prohibitions. Aayaat to make us think, reflect, weep, fear, hope, love, and even fall down in prostration! How can we recite all of this without feeling!? When we recite an aayah of Quran we should try to feel and express the full message behind that aayah. Perhaps some of us lack confidence. I believe that this lack of confidence comes partly from not knowing the rules of Tajweed accurately and becoming so concerned about making mistakes and partly from not comprehending the meaning of what we are reciting. So let us work hard to remove these two obstacles by learning Tajweed and working towards learning Arabic in order to truly feel the essence of the Quran.
One of the privileges that the student is rewarded with, provided that they complete the course following the proper rules and somehow stands out from the crowds of students eager for knowledge, they get admittance into the Imam's intense memorization program---make duaa inshaa Allah :)