There are several sources for us to gain knowledge.
You cannot gain anything without efforts.
Those who think before speaking and act wisely gain success in life.
We should constantly make efforts to gain the right knowledge of life, of ourselves, of the world with the help of books, self-contemplation and company of the wise.
Health once lost is difficult to gain.
Loss and gain are brothers twain.
We should take both our gain and loss with equal calm.
Politeness is the key to gain respect and appreciation.
If we make persistent efforts to gain our subject, surely our efforts will be crowned with success.