Mistakes in words which are clear and inconspicuous, usually changing the meaning. Mistakes related to correct pronunciation of letters so that letters are not mixed up. Scholars, and the ordinary Muslims should avoid these.
Examples of Clear mistakes:
• Changing one letter into another, or a short vowel (harakah) into another, (changing Fathah into Damma or the letter Qaaf into Kaaf etc)
• Not observing the elongations (Madd) at all. Reciting them quickly as if there is no Madd so that they turn into the length of a vowel.
• Making a madd letter out of a normal harakah.
• Stopping or starting at an incorrect place so that the meaning is spoilt. Like stopping at 'Laa ilaaha' (There is no God), without completing 'illallaah' (except Allah).
Mistakes which are to do with perfecting pronunciation and are not obvious. Known only by those who have studied tajweed rules or experts in this field. Ordinary Muslims may not know these or perceive these as mistakes.
Examples of Unobvious mistakes:
• Not being totally exact with the elongation of letters: (Making the Madd shorter or longer by a 1/2 or even 1/4 degree etc.)
• Not observing the attributes of each letter perfectly: (Slightly rolling the Raa', or exaggerating the 'N' sound in Noon etc.)
• Not observing the rules with which to pronounce letters when they are next to each other (like not merging certain letters that should be merged (idghaam) and not clearly pronouncing those which should be clearly pronounced (ith-haar) etc.)
• Making light letters sound heavy and heavy letters sound light (Except if by doing this you change a letter into another; in this case it would be an obvious mistake.)
And of the proofs that the scholars bring to show the obligation of Tajweed and that it is an established Sunnah is that Allah says in the Qur'an, the meaning of which is:
'And recite the Qur'an (aloud) in a (slow and melodious) style (tarteela)' (Surah Muzzammil, aayah 4)
Ali ibn Abi Talib (radi Allahu 'anhu) said in the explanation of this aayah:
"at-Tarteel is Tajweed of the letters and knowing where to stop (correctly)".
And of the proofs also is that Allah says in the Qur'an, the meaning of which is:
'Those who We have given the Book to, give it its right in recitation ( recite it as it should be recited)' (Surah al-Baqarah, aayah 121)
And of the rights of reciting correctly is reciting it the way it was revealed.
There are various ahadeeth also showing us the importance of Tajweed.
Umm Salamah was asked about the recitation of the Prophet (sallallaahu alaihi wa sallam) and she described it as a recitation 'clearly-distinguished letter by letter'.
Sa'eed bin Mansoor relates in his Sunan that a man was reciting the Qur'an to Abdullah bin Mas'ood and he recited
"Innamas sadaqaatu lil fuqara-i wal masaakeen", so Ibn mas'ood said: "This was not how the Messenger of Allah (sallallaahu alaihi wa sallam) recited it to me!" So the man asked,
"How did he read it to you oh Aba Abdir-Rahman?" So he said "Lil Fuqaraaaa-i wal masaakeen", he elongated the word Fuqaraa and the knowledge of the different lengths of elongation (mudood) is also from the rules of Tajweed.
Reciting the Qur'an melodiously
1. The Prophet (sallallaahu alaihi wa sallam) used to recite the Qur'an in slow, measured, rhythmic tones as Allah had instructed him, not hurriedly, but rather "he would recite a surah in such slow rhythmic tones that it would be longer than it would seem possible."
2. He would stop at the end of each aayah.
3. He commanded people to recite in a beautiful voice in a pleasant melodious tone. He said "Beautify the Qur'an with your voices [for a fine voice increases the Qur'an in beauty]"
and he said
4. " He who does not recite the Qur'an in a pleasant tone is not of us." Unfortunately all to often we find people reciting the Qur'an quickly and without changing their tone and without any feeling.
5. We should put all our efforts into reciting the Qur'an with as much feeling as we can! Have you ever prayed behind an Imam who read with feeling? Well the Prophet (sallallaahu alaihi wa sallam) said "Truly the one who has one of the finest voices among the people for reciting the Qur'an is the one whom you think fears Allah when you hear him recite."
6. And once when the Prophet (sallallaahu alaihi wa sallam) 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."
Let us remember, that the Qur'an is the word of Allah. In it we find exhortations, warnings, glad-tidings, parables, stories of the past, commands and prohibitions. Aayaat to make us think, reflect, cry, fear, hope, love, fall down in prostration! How can we recite all of this without feeling!? When we recite an aayah of Qur'an we should imagine that we are trying to feel and convey the full message behind that aayah. Perhaps some of us don't feel confident. I believe that this lack of confidence comes partly from not knowing the rules of Tajweed correctly and so fearing that we will make mistakes and partly from not understanding 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.