Wikipedia:Don't overuse quotes
Many articles on Wikipedia use quotations to represent opinions of significant people. This is a mistake. If you want to find, or add quotes, there is a sister project to Wikipedia entirely devoted to them: Wikiquote.
Why to not use quotations
Wikipedia is a tertiary source that relies on authoritative, published secondary sources such as newspapers and peer-reviewed journals, rather than primary sources and original research. Quotations are often taken from primary sources such as personal diaries or interviews. The problem with such sources is that they may not be fully representative of an individual's views. It may be that they changed their views throughout their life, or held conflicting views at once.
Editors with an axe to grind sometimes use quotes from an individual's early life, personal papers, or little-known interviews to show that they support a particular position, when the truth may be much more complicated. In such cases, it's always better to provide a summary of the individual's views, ideally sourced from a reputable biography, rather than counter-quotes intended to 'rebalance' the article.