A. Plenty. Here are 3 quotes.
1) If someone says: “I’ve tried, but not succeeded” Don’t believe him.
If someone says: “I haven’t tried, but I’ve succeeded” Don’t believe him either.
Only someone who says: “I’ve tried and succeeded” should be believed. (Talmud Megilla 6b)
2) “Study your Heart’s Desire” – you do best in the field you enjoy. (Talmud Avoda Zara 19a)
3) “Seven times the righteous fall, but rises again” – Don’t let it stop you! (Proverbs 24:16)

Note: the quote in #1 is one of the 12 Torah passages the Lubavitcher Rebbe encouraged all Jewish children to learn by heart.