imam sadegh (a.s.) says:
صَلاحُ حالِ التَّعایُشِ و التَّعاشُرِ مِلاَمِکْیال ثُلْثَاهُ فِطْنَةٌ وَ ثُلْثَهُ تَغافُلٌ
improving the situation of life and association is possible through using a measure, two third of which is vigilance and one third of which is negligence.(1)
brief des c r i p tion
no work is started without any study, plan and vigilance, and also no work is accomplished without negligence. iis more clear and better to say if we want to work without investigation and carefulness, we will not succeed. but if we want to linger for all possible probabilities and unpredicted events when performing the works, we would not be able to do a work easily, and have to study for years to do something or to select a friend, partner, spouse and such like. so it is said two third vigilance and one-third negligence.