פִּקּ֘וּדֵ֤י יְהוָ֣ה יְ֭שָׁרִים מְשַׂמְּחֵי־לֵ֑ב מִצְוַ֥ת יְהוָ֥ה בָּ֝רָ֗ה מְאִירַ֥ת עֵינָֽיִם׃
Les préceptes de l’Éternel sont droits: ils réjouissent le cœur. Le commandement de l’Éternel est lumineux; il éclaire les yeux.
Or HaChaim
Let us now go back to the main subject under discussion, the Israelite's imagination as applied to matters concerning his libido. The more he thinks about this subject the more his desire becomes aroused making it harder for his רצון, will, to control his emotions, the urges rooted in his being flesh and blood. Whereas normally, one needs to concentrate on the subject of G'd's commandments in order to ensure that one fulfils them in the best way possible, in this case one must avoid even thinking about it so that one does not see the object of one's desire with one's eyes. The moment one looks upon the object in question one places one's innocence in jeopardy. We know that King David fell victim to his carnal urges as a result of looking at Bat Sheva (Samuel II 11,2) bathing on the roof of her house. Up until that moment David's heart which had been devoid of lust had not been aroused. He did what he did only as a result of what he saw with his eyes. The moment one begins to think carnal thoughts one's temptation is reinforced, and as a result this makes preoccupation with carnal thoughts appear as something natural. The wise Solomon was fully aware of this and this is why he wrote in Proverbs 1,10: "my son, if sinners entice you, do not consent." He meant that one should not engage in arguing with anyone who tries to entice one to sin. The mere fact that one argues about it already strengthens the forces of temptation. When David said in Psalms 19,9 that the precepts of G'd are clear and brilliant, he referred to the expressions דבור and אמירה respectively, i.e. that on the one hand G'd gave clear directives, i.e. like the decree of a king, דבור; on the other hand, He also phrased this commandment as אמירה, as a soft-spoken one, the kind of tone one adopts with highly placed people and He asked Moses to tell them that He is their G'd, i.e. to bestow His Holy Name on them. There is no greater tribute G'd can pay to a people.
Rabbeinu Bahya
ביום הגמל את יצחק, ”on the day Yitzchak was weaned.” It is customary for people to throw a party when a baby is born or on the day it is being circumcised, in order to honour the fulfillment of the commandment. We need to explore why Avraham had waited so long (24 months according to Rashi) before throwing this party. It is possible that he delayed because he wanted to wait until the day Yitzchak would begin to study the Torah. This is not as strange as it may appear at first glance as according to tradition Avraham himself was only three years old when he first recognised that there is a G’d in heaven who is the prime cause of the universe’s existence (compare Nedarim 32). This is why he did not make this festive meal either on the day of Yitzchak’s birth or on the day he was circumcised. He wanted the weaning to coincide with the joy of introducing his son to Torah-study, a joy of which David said פקודי ה' משמחי לב, “The Lord’s commandments fill the heart with joy” (Psalms 19,9). We have another verse in Isaiah 28,9 את מי יורה דעה, ואת מי יבין שמועה? גמולי מחלב, ”to whom would he give instruction? To whom expound a message? To those newly weaned from milk.” As soon as the baby is weaned it becomes sanctified to be separated and trained in the service of the Lord. From that point on Yitzchak would become potentially ready to be a burnt-offering for G’d according to Bereshit Rabbah 64,3. As such he was not allowed to leave the sacred precincts of the Holy Land just as such an offering must not leave the sacred precincts of the Holy Temple.
Or HaChaim
Our verse also contains an allusion to Psalms 19,9: "The precepts of G'd are just, rejoicing the heart." Accordingly, we have to read the verse as if it said: "you will be joyful as a result of hearkening to G'd's commandments." The joy may even be the reward, עקב, of your Torah-study. This may be an aspect of what we are told in Avot 4,2 that performing one commandment results in that person performing more commandments. This next מצוה may be the joy one experiences.
Rashi
Rejoicing. That he should be happy with in his lot30Alternatively, I extolled the virtuous trait of rejoicing, i.e., the trait of being able to accept every occurrence in life with happiness and joy. (Derech Hachayim) and engage in the “upright commands,” which “cause the heart to rejoice,”31Tehillim 19:9. and he should not be immersed in increasing his wealth by means of usury, interest and robbery.32The Gemara in Maseches Shabbos 30b sees an apparent contradiction between this verse which extolls the concept of rejoicing, and the verse above [2:2], which states, “and of joy, what does it accomplish.” The Gemara explains that the verse here is speaking of a celebration or rejoicing of a mitzvah, e.g., a marriage, therefore rejoicing is extolled, whereas verse 2:2 above speaks of rejoicing without purpose, and is therefore frowned upon. Whoever is not happy with his lot and is immersed in amassing wealth, eventually commits the sins of robbery, fraud, and usury. Also, one who is not happy with his lot concerning the love of his wife, is immersed in [a passionate lust for] women, and harbors sinful thoughts about married women.