Importance of Learning Arabic

Shaykh Uthaymeen said:
"From the benefits of learning the Arabic language is correction of the tongue with the Arabic tongue which the speech of Allah was revealed in. Because of this, understanding the Arabic language is extremely important. But the sciences of the Arabic language are difficult in the beginning and becomes easy thereafter. It is the example of a house made of cane (the likes of sugar cane), but its door is made of steel. Meaning, it is difficult for one to enter, but once one does, is is then made easy. Due to this, I encourage the student to learn the foundations of the language in order to make the rest easy for him/her."
Courtesy the SALAM Yahoo Group
From "The Status of the Arabic Language in Islam", Shaykh Ibn Taymiyyah:
".....the Arabic language itself is part of Islam, and knowing Arabic is an obligatory duty. If it is a duty to understand the Qur‘an and Sunna, and they cannot be understood without knowing Arabic, then the means that is needed to fulfil the duty is also obligatory. There are things which are obligatory o n all individuals (fard ‘ayn), and others which are obligatory o n the community or Umma (fard kifayah, i.e., if some people fulfil them the rest are relieved of the obligation). This is the meaning of the report narrated by Abu Bakr Ibn Abi Shaybah who said: ‘Isa Ibn Yunus told us from Thawri from ‘Umar Ibn Yazid that ‘Umar wrote to Abu Musa al-Ash’ari and said: “Learn the Sunna and learn Arabic; learn the Qur‘an in Arabic for it is Arabic.” According to another hadith narrated from ‘Umar, he said: “Learn Arabic for it is part of your Religion, and learn how the estate of the deceased should be divided (fara‘id) for these are part of your Religion.” This command of ‘Umar, to learn Arabic and the Shari’a combines the things that are needed, for Religion involves understanding words and actions. Understanding Arabic is the way to understand the words of Islam, and understanding the Sunna is the way to understand the actions of Islam…”
Courtesy THM SadaqaGroup

Sheikh ul Islam Ibn Taymiyyah said:
The Salaf would admonish their children when they made Arabic grammatical mistakes. Due to this, we are ordered, whether it be an obligation or a recommendation, to preserve the Arabic (grammatical) laws, and to correct the tongues that have deviated from the correct speech. By doing so, we preserve the methodology of understanding the Quran and the Sunnah. We also preserve the following of the Arab in their manner of (correct) speech. If people were left with their grammatical mistakes, this would be considered a great deficiency and despicable mistake. (source: Majmoo' Al Fatawa 32/252)