It is confirmed that the Messenger of Allaah (sallAllaahu `alayhi wa sallam) said,
ما أسفل من الكعبين من الإزار ففي النار
"What is below the ankles from the Izar is in the Fire." (Al-Bukhari no. 5787)
He (sallAllaahu `alayhi wa sallam) also said,
ثلاثة لا يكلمهم الله يوم القيامة ولا ينظر إليهم ولا يزكيهم ولهم عذاب أليم قال فقرأها رسول الله صلى الله عليه وسلم ثلاث مرار قال أبو ذر خابوا وخسروا من هم يا رسول الله قال المسبل والمنان والمنفق سلعته بالحلف الكاذب
"There are three people that Allaah will not speak to on the Day of Judgement, will not look at them, will not purify them; and for them is a painful punishment: one who lets his garment hang below his ankles, the Mannan in what he gives, and the Munffiq who does his business with false oaths." (Muslim no. 106)
The Hadeeths with this meaning are many proving the prohibition of Al-Isbal, without qualification. If someone says they are not doing it from pride, they do not know that this practice leads to pride, that it is a form of waste regarding the garment, and that it makes the garment vulnerable to any impurities that may he on the ground.
Had that person done it from pride, the matter would be more severe and the sin would be greater, because of the saying of the Prophet (sallAllaahu `alayhi wa sallam)
من جر ثوبه من الخيلاء لم ينظر الله إليه يوم القيامة
"Whoever drags his Izar out of arrogance, Allaah will not look at him on the Day of Judgement." (Al-Bukhari no. 5784 and Muslim no. 2085)
The limit for this is the ankles, so a Muslim male is not allowed to let his clothes fall below his ankles due to the Hadeeths mentioned.
As for a woman, it is allowed for her to lower her garment in order to cover her feet. As for what is reported from As-Siddiq (Abu Bakr), may Allaah be pleased with him, he said to the Prophet (sallAllaahu `alayhi wa sallam): "My Izar falls unless I take care (to hold it up)." The Prophet (sallAllaahu `alayhi wa sallam) said to him,
لست ممن يصنعه خيلاء
"You are not one of those who does it out of conceit." (Al-Bukhari no. 5784 and Abu Dawud no. 4085)
This only means that the person whose Izar hangs low does not enter under the warning of punishment if it happens unintentionally and if he tries to keep it up. But whoever else does it is accused of arrogance, or if not, then his action leads to arrogance, and it is Allaah Almighty alone who knows what is in the hearts.
The Prophet (sallAllaahu `alayhi wa sallam) warned against Al-Isbal in Hadeeths without making any qualification for the prohibition — he didn't say it is allowed if it is done without pride.
It is obligatory upon every Muslim to warn against that which Allaah has forbidden, to stay far away from anything that leads to His anger, and to stop at the limits Allaah has set. He does this hoping for Allaah's reward and fearing His punishment, acting upon Allaah the Almighty's saying:
وَمَا آتَاكُمُ الرَّسُولُ فَخُذُوهُ وَمَا نَهَاكُمْ عَنْهُ فَانتَهُوا وَاتَّقُوا اللَّهَ إِنَّ اللَّهَ شَدِيدُ الْعِقَابِ
"And whatsoever the Messenger gives you, take it; and whatsoever he forbids you, abstain (from it). And have Taqwa of Allaah; verily Allaah is Severe in punishment." [Al-Hashr 59:7]
وَمَن يَعْصِ اللّهَ وَرَسُولَهُ وَيَتَعَدَّ حُدُودَهُ يُدْخِلْهُ نَارًا خَالِدًا فِيهَا وَلَهُ عَذَابٌ مُّهِينٌ
"And whosoever disobeys Allaah and His Messenger, and transgresses His (set) limits, He will cast him into the Fire, to abide therein; and he shall suffer a disgraceful torment." [An-Nisa' 4:14]