Conscience is the sense of Right and Wrong !
Nature has awarded us with such a great tool called conscience.
It generates positive and negative signals for the actions you perform.
When you buy food for the hungry with sincerity,
when you give some money to an orphan with love,
when you pay the education fee for a poor student,
when you give some money to a free services hospital,
your conscience sends you a thank you signal and you feel good about yourself which gives birth to your 'inner' satisfaction.
It is said that you don't really achieve deep happiness by spending on yourself; you get it when you spend on others !!! And even you achieve greater degree of contentment when you spare your time from your busy life, visit any orphans or widows place, hospitals and other deserving people of society and then spend your money on them.
From religious perspective, I believe that almost all of the religions have defined the principle of spending on humanity in order to get tranquility, serenity and prosperity. However, we the unfortunate people, the materialistic minds, keep calculating our money and assets several times a day which increases our greed level and eventually deprives us from peace of mind. It won't be wrong if I say that our extreme love for money and being materialistic is the real killer of our happiness.
To cope up with this, the wise people highly recommended to allocate a little portion (5% of your earnings) for the genuine causes.
While the conscience claps for our good acts, it must generate red signals for our bad acts too. And if that is not happening then something is seriously wrong in our roots of faith. Considering the fact that a clean and active conscience is the best pillow, we must empower it by more positive acts as well as with daily self audits when our head is on the pillow at the end of each day.