It's in there somewhere

I know this verse... "I will hold your truths in my heart, so that I will not sin against you.".... For the life of me I can't remember where it is in the bible... Proverbs... something... That is proof that I need to memorize scripture more. Whenever I go to my friend Noemi for advice, she can always give me advice straight from the bible.
I want to be able to do that for my girls. I want to be able to give them not my opinion, but what God says on the matter. I guess my next step would be to get more into the word and memormize scripture.

2 Timothy 4:2
Preach the Word; be prepared in season and out of season; correct, rebuke and encourage—with great patience and careful instruction.