Say not: “When I have free time I shall study”, for you may perhaps never have any free time
If not you, who? If not now, when?
What you yourself hate, don't do to your neighbor. This is the whole law; the rest is commentary. Go and study.
Do not unto others that which is hateful unto thee.
The shy man will not learn; the impatient man should not teach.
Moreover he saw a skull floating on the surface of the water and he said unto it: Because you drowned others they drowned you; and those that drowned you will eventually be drowned.