Deuteronomy 13:5

You shall walk after the service of the Lord your God, and Him shall you fear, and keep His commandments, hearken to His word, pray before Him, and cleave unto His fear.

after God your God must you walk you must imitate His acts, to the best of your ability, and pursue His ways.

Him must you revere fearing to question “Why is this?”

His commandments must you keep i.e., the commandments which are ends in themselves.

His voice must you obey i.e., the commandments which remind us of those ends.

Him must you serve in action.

and to Him must you cleave in your heart — in the first life, and in the afterlife.

AFTER THE ETERNAL YOUR G-D SHALL YE WALK. This is a commandment that we follow His counsel, and of Him alone shall we inquire concerning every hidden thing and inquire concerning the future, as it is written, and she went to inquire of the Eternal; because the people come unto me to inquire of G-d. And so did the Israelites do with the prophets, [as it is said,] Is there not here a prophet of the Eternal, that we may inquire of the Eternal through him?; that the Eternal thy G-d may tell us the way wherein we should walk, and the thing we should do. And in the Sifre it is stated: 85. “After the Eternal your G-d [shall ye walk] — this refers to the cloud [of Glory].” This is as we have explained, that we are to hearken to the “voice” of His signs and follow His counsel.

AND HIM SHALL YE FEAR. You are to believe that it is He in Whose hand is the soul of every living thing, and it is in His power to kill and to make alive, visiting iniquity, and rewarding for meritorious deeds.

AND HIS COMMANDMENTS SHALL YE KEEP. This refers to the Law of Moses.

AND UNTO HIS VOICE SHALL YE HEARKEN — to do whatever He commands us to do aside from the Torah, such as Samuel said [to Saul], Thou hast done foolishly; thou hast not kept the commandment of the Eternal thy G-d [referring to a commandment transmitted to Saul by Samuel]. It is this which is explained further, A prophet will the Eternal raise up unto thee, of thy brethren, like unto me; unto him ye shall hearken, and it states, And it shall come to pass, that whosoever will not hearken unto My words which he shall speak in My Name, I will require it of him, Verse 19. meaning that he will be liable to death by the hand of Heaven, and as it happened because of the prophet’s command, “Smite me, and wound me by the word of the Eternal” [and when the man refused to obey he was slain by a lion]., Verse 36. And so also the Rabbis said in the Sifre: 85. “And unto His voice shall ye hearken — the voice of His prophets.”

אחרי ה' אלוקיכם תלכו, similarly phrased to והלכת בדרכיו in Deut. 28,9. You are not to seek out new paths which the “prophet” or “dreamer” employs to make you depart from the ways of the Lord.

ואותו תיראו, even though the person who now claims to be a prophet had previously been considered as a pious and thoroughly G’d-fearing individual. Your prior esteem of him and his views must turn into total rejection and you must allow your awe and reverence for G’d and His words to outweigh any argument he may present. ואת מצותיו תשמורו, so that you will only observe His commandments and not any new ones claimed to be His by the new “prophet.” This refers in particular to matters involving idolatry where the most minute deviation automatically challenges the totality of Torah and all of its laws.

ובקולו תשמעון, you are to carry out all the instructions given to you by properly accredited prophets and to listen to their commands, such as to Elijah at Mount Carmel, and not to the instructions of anyone canceling any of G’d’s commandments.

ואותו תעבודו, exclusively. You cannot simultaneously serve any other deity as spelled out in Exodus 22,19 זובח לאלוהים יחרם, “if anyone is found offering sacrifices to any other deity he is guilty of death.”

ובו תדבקון, the objective of all your activities must be to carry out His will unaffected by any prior hostility.