ס֣וּר מֵ֭רָע וַעֲשֵׂה־ט֑וֹב בַּקֵּ֖שׁ שָׁל֣וֹם וְרָדְפֵֽהוּ׃
éloigne-toi du mal et fais le bien, recherche la paix et la poursuis.
Radak
Who doth not walk in the counsel of the wicked: – He first recounts the evil way, as he also says likewise elsewhere (Ps. 34:15): “Depart from evil and do good,” because man first learns, from his youth up, the way of the desires of this world, to eat and to drink and to be merry, and in them grows up, as it says (Gen. 8:21): “for the imagination of man's heart is evil from his youth.” So and (then) when man arrives at years of discretion and begins to distinguish good and evil, he warns him to depart from the way of the wicked and not to follow their advice. Now the wicked are those who are feverishly anxious to amass wealth and the desires of whose heart are in this world, who do not distinguish between right and wrong, but for money's sake steal and plunder and murder because of the exceeding restlessness of their heart. For the root meaning of רשׁע (wickedness) is “restlessness,” as “When He giveth quietness who then can disturb?” (ירשׁיע disquiet) (Job 34:29); “and whithersoever he turned himself he vexed (ירשׁיע disquieted) them” (I Sam. 14:47); “neither shall violence (רשׁע) deliver its masters” (Koheleth 8:8); “Be not overmuch engaged (תרשע) in worldly matters” (ibid. 7:17). It is on this account that he conjoins walk with wicked; and with these he joins counsel, for they counsel the children of men to listen to them and they shew them specious counsel (to the effect) that it is a fine thing to gather riches and to be merry. And man is largely deceived in this, for the good which is visible to his eyes appears best to him and he does not look to its end. And he (the Psalmist) Says:
Kli Yakar
And perhaps it is a matter of peace, as they expounded on the verse seek peace and pursue it (Psalms 34:15), for peace is not like other commandments because for all other commandments such as tzitzit, mezuzah, and challah, if they come before you, you are obligated to perform them, but you are not obligated to pursue them. However, with peace, you are obligated to pursue it (Vayikra Rabbah 9:9). We should provide a reason for this matter: Why is peace different from all other commandments in the Torah? It will be properly explained if we say that this peace refers to making peace between Israel and their Father in Heaven through repentance. Therefore, you need to pursue it from two perspectives: First, because the sinner will never acknowledge guilt in his soul and will never see his own fault as you see it, therefore you must pursue him, for he will not pursue you. Second, because you need this peace since all of Israel are guarantors for one another. Our Sages said (Yoma 86b): Great is repentance, for even when an individual repents, he is forgiven and so is the entire world, as it is said (Hosea 14:5): I will heal their backsliding, for My anger has turned away from him. If so, this peace is for your benefit, and it is only right that you should pursue it.
Malbim
For the most important aspect of a person's worship of God is that he should do good for its own sake and for the sake of the Profound Statute issued by the Supreme Lawgiver; and principally for the sake of His great Name (2Chronicles 6:32). However, this would not be the case if a person's actions were guided by considerations of reward or fear of punishment. For he would then be serving not God but himself and this is not the sort of worship God desires. If the reaction to evil acts was immediate (Ecclesiastes 8:11) and God meted out punishment to the wicked at once, nobody would dare (Jeremiah 30:21) to do evil for fear of the immediate retribution that would follow. Similarly, everyone would try to do good because they knew they would be rewarded instantly. The deed would not be performed for the sake of God, nor would there be any meaning to reward and punishment, seeing that all would be bound to act as they did out of fear of punishment or hope of reward. Nor would there be any meaning to free-will and trial, though they were the substance of God's purpose in creating man: that the heart's inclination should tempt a person to do evil and he should feel free to do so, but that nevertheless he should refrain and turn away from evil (Psalms 34:15), out of respect for God and His divine ordinances. Therefore, He endowed man's mind with everything, except the knowledge of how God acts (Ecclesiastes 3:11) with regard to the reward of the righteous or the punishment of the wicked. And so there are evil-doers who prosper and wicked persons who are praised in public for what they have done and God's Providence is concealed and hidden from the sight of most people. Contrariness beguiles understanding, causing it to deny Providence and to declare that the world runs itself (TB Avodah Zarah 54b); that everything depends on heredity, nature and the stars; that the Lord is on high, His glory is above the heavens (Psalms 113:4), and He does not govern those down below; not to mention the other charges made by heretics. As proof, they all cite the disorder and capriciousness of Providence, namely, that the righteous languish and the wicked prosper.
Rashi
they walked in His ways Although they committed no injustice, their reward is incomplete unless they walked in His ways. And so he says (above 43:15): “Shun evil and do good.” Even though you shun evil, everything is not complete unless you do good. Midrash Aggadah.