Génesis 12:5 Halajá: Mishneh Torah, Foreign Worship and Customs, Sefer HaMitzvot & Sefer HaMitzvot HaKatzar

As soon as this giant was weaned he commenced to busy his mind, in his infancy he commenced to think by day and by night, and would encounter this enigma: How is it possible that this planet should continuously be in motion and have no leader—and who, indeed, causes it to revolve, it being impossible that it should revolve itself? Moreover, he neither had a teacher nor one to impart aught to him, for he was sunk in Ur of the Chaldeans among the foolish worshipers of stars, and his father, and his mother, like all the people, worshiped stars, and he, although following them in their worship, busies his heart and reflects until he attains the path of truth, and, by his correct thinking, he understood when he finally saw the line of righteousness. He knew that there is One God; He leads the planet; He created everything; and in all that is there is no god save He. He knew that the whole world was in error, and that the thing which caused them to err was, that their worshiping the stars and the images brought about the loss of the truth from their consciousness. And, when Abraham was forty years old he recognized his Creator. After he came to this comprehension and knowledge he started to confute the sons of Ur of the Chaldeans, and to organize disputations with them, cautioning them, saying: "This is not the true path that you are following", and he destroyed the images, and commenced preaching to the people warning them that it is not right to worship any save the God of the universe, and unto Him alone it is right to bow down, to offer sacrifices, and compound offerings, so that the creatures of the future shall recognize Him. Moreover, it is right to destroy and break in pieces all of the images, so that the whole population of the future be not led to an error like unto these who imagine that there is no God save these images. When he had them subdued by his well supported contentions, the king tried to put him to death, but he was saved by a miracle, and went hence to Haran. There he stood up anew and called out in a great voice to the whole world, to let them know that there is One God for the whole universe, and unto Him it is proper to render service. And thus he went onward with his proclamations from city to city, and from government to government, until he attained the land of Canaan amidst his outcry, even as it is said: "And called there on the name of the Lord, the Everlasting God" (Gen. 21.33). When the people who congregated about him asked him concerning his preachments, he replied by imparting knowledge to each and every one according to his mentality, to the end that he was able to turn him to the path of truth, until there congregated about him thousands, even tens of thousands, and they became the people of Abraham's household, in whose heart he implanted this great cause, concerning which he compiled books, and which he imparted to his son Isaac.³Nedarim, 32a. C. Isaac, from his seat of learning, gave instructions and admonitions. And Isaac, in turn, imparted it to Jacob and appointed him head master, who, at his seat of learning, gave instructions and supported all who flocked to him. And Jacob our father instructed all his sons, but separated Levi and appointed him head master, and established him in a seat of learning where to instruct in the path of the Name and in the observance of the charges of Abraham. He, moreover, commanded his sons not to interrupt the succession of the sons of Levi to the presidency of the school so that the learning be not forgotten. So did the movement advance intensely among the sons of Jacob and their followers that the world saw a God-knowing nation called into existence, until Israel spent a long time in Egypt, when they turned to be instructed in their practice and to worship the stars as they did, save only the tribe of Levi, which remained faithful to their ancestorial charge; for the tribe of Levi at no time worshiped stars. Verily, in but a short space of time, the root which Abraham had planted would have been uprooted, and the sons of Jacob would have turned to the universal error and wandering; save because of the Lord's love for us, and because He observes the oath of covenant with Abraham our father, He appointed Moses our Master lord of all prophets, and made him His messenger. After Moses our Master was endowed with prophecy and the Lord chose Israel as an inheritance, He crowned them with commandments, and made known to them the way to serve Him, and what will be the judgment rendered against idolatry and all its erring devotees.³

The 3rd mitzva is that we are commanded to love G‑d (exalted be He), i.e. to meditate upon and closely examine His mitzvos, His commandments, and His works, in order to understand Him; and through this understanding to achieve a feeling of ecstasy. This is the goal of the commandment to love G‑d. [We can see that meditation is the way to create this feeling of love1 from] the Sifri: "From the statement, 'You shall love G‑d your Lord'2, can I know how to love G‑d? The Torah therefore says, 'and these words which I command you today shall be upon your heart'3; i.e. that through this [meditation about His commandments] you will understand the nature of 'the One Who spoke, and thereby brought the world into being.' "From this it is clear that meditation will lead to understanding, and then a feeling of enjoyment and love will follow automatically [since the second verse explains the way to reach the goal of the previous verse.]Our Sages also said that this mitzvah includes calling out to all mankind to serve G‑d (exalted be He) and to believe in Him. This is because when you love a person, for example, you praise him and call out to others to draw close to him. So too, if you truly love G‑d — through your understanding and realization of His true existence — you will certainly spread this true knowledge that you know to the ignorant and the foolish.[We see that this mitzvah includes spreading love for G‑d to others from] the Sifri: " 'You shall love G‑d,' i.e. make Him beloved among the creatures as your father Avraham did, as it is written, 'The souls that he made in Charan.'4"The meaning of this Sifri: Avraham, as a result of his deep understanding of G‑d, acquired love for G‑d, as the verse testifies, "Avraham, who loved Me"5. This powerful love therefore caused him to call out to all mankind to believe in G‑d. So too, you shall love Him to the extent that you draw others to Him.

It is a positive commandment to love God, may He be blessed, with all one's heart, and all one's soul, and all one's might. As it is said (Deuteronomy 6:5): "You shall love the LORD your God with all your heart and with all your soul and with all your might." The way to love Him is to meditate on His acts until one contemplates them to the degree to which he is able - when the heart is aflame with the love of Him. This is the love which is incumbent upon us. One should direct all of his thoughts toward the love of God, may He be blessed. A person can only love the Holy One, blessed be He from the knowledge with which he knows Him, so in proportion to that knowledge will be the love: if [the knowledge is] small, [the love will be] small; if great, great. Therefore, a person needs to focus himself on understanding and comprehending, through wisdom and known philosophies, the honor of his Master, in proportion to the ability which he has to understand and attain. This is one of the commandments which a person is obligated in at all times, at every moment. Included in this commandment is [the requirement] to bring people close to His service, may He be blessed, and to love Him for what he has created, as our forefather Avraham, peace be upon him, did, as it is said (Genesis 12:5): "And the souls which he created in Haran." Because of this, the Holy One, blessed be He, called Avraham His beloved, as it is said (Isaiah 41:8): "Avraham my beloved."