All are gurus to us, the wicked by their evil deeds say 'do not come near me'. The good are always good, therefore all are like gurus to us.
Mathematics is the poetry of logical ideas.
The first duty of the sovereign, that of protecting the society from the violence and invasion of other independent societies, can be performed only by means of a military force.
做伟大的事情很困难,但指挥伟大的事情更困难。
The poor perpetually sell their time cheaply, yet can never buy it back.