Quotation su I Cronache 28:9

As the verses say: "Guard your heart above all else, for it determines the course of your life" (Mishlei 4:23), and "for the imagination of man's heart is evil from his youth" (Bereishis 8:21), "For I know their imagination.." (Devarim 31:21), "for the L-rd searches all hearts, and He understands all the imaginations of the thoughts of every creation; [if you seek Him, He will be found to you, and if you forsake Him, He will abandon you forever]" (Divrei Hayamim 28:9), "Rather,[this] thing is very close to you; it is in your mouth and in your heart, so that you may do it" (Devarim 30:14), "And now, O Israel, what does the L-rd, your G-d, demand of you? Only to fear (revere) the L-rd, your G-d" (Devarim 10:12), and fear (reverence) is in the heart, reflections, and thoughts. Therefore, my brother, strive that all of your actions be devoted only to the blessed Creator, so that your exertion will not be for nothing, and your efforts not for falsehood, as written "Why should you weigh out money for that which is not bread and your toil without satiety?" (Yeshaya 55:2).

And this is the letter which the above-mentioned Rabbi sent from the Holy Land to Castile, when his son was staying before the kind (in his service):- May God bless you, and preserve you from sin and punishment. Behold, our master, King David, bore a son, wise and of understanding, like unto whom there was never one before or after. Nevertheless he said to him (1 Kings ii. 2): 'And keep the charge of the Lord thy God,' etc. He also said to him: 'And thou, my son, know the God of thy father' (1 Chron. xxviii. 9). Now, my son, if thou wilt measure thyself with Solomon, thou wilt find thyself a worm, - not a man, merely an insect, nevertheless, if thou wilt seek God, he will make thee great; and if thou wilt forsake him, thou wilt be turned out and forsaken. My son, be careful that thou readest the Shema morning and evening, as well as that thou sayest the daily prayers. Have always with thee a Pentateuch written correctly, and read therein the Lesson for each Sabbath...