Who does not grow, declines.
A single candle can light a thousand more without diminishing itself.
If not you, who? If not now, when?
Say not: “When I have free time I shall study”, for you may perhaps never have any free time
Golden Rule”: “That which is hateful to you, do not do to your fellow. That is the whole Torah; the rest is the explanation; go and learn.
The shy man will not learn; the impatient man should not teach.