Quotes from Sahabah:

source of these quotes:
http://islamicquotes.wordpress.com

On Sinning:

Abdullah bin Abbas said: “You who commit a sin, do not feel secure about the results, for what goes along with the sin is more serious than the sin itself. Your lack of shame before the angels, who witness you when you commit the sin, is more serious than the sin itself. Your laughter when you sin, as you forget the punishment of Allah is more serious than the sin itself. Your delight if you get a chance to sin, is more serious than the sin itself. Even your disappointment, if you miss a chance to sin is more serious than the sin itself.”

Be content with what you have,Be satisfied with your dwelling place to accommodate your enterprise,Restrain your tongue,And shed tears of regret regarding past sins you committed knowingly, and those you do not recognize… ‘Abdullah Ibn Mas’ud

On Taqwa:

Abdullah bin Mas’ud – “Taqwa is to obey Allah, so that He is not disobeyed, to remember Allah, so that He is not forgotten, and to thank Allah, so that no ingratitude is shown to Him”
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“Whoever does 4 things is fortunate in this world and in the Hereafter.

1. Reciting Laa ilaaha illallaah Muhammadur-Rasoolullaah; Inna lillaahi wa inaa ilaihi raaji’oon when any mishap befalls them;
2. saying la hawla wa laa quwwata illa billahil ‘azeem – alhumdulillahi rabbil alameen when any gift is bestowed upon them;
3. saying bismillahir-rahmaanir-raheem when beginning any work; and
4. saying astaghfirullahil ‘azeem wa atoobu ilayhi when any sin is noticed.”

['Abdullah bin 'Amr bin al-Aas]