Thus, the words of Allah, "eat the lawful (and) good things...
Thus, the words of Allah, "eat the lawful (and) good things out of what is in the earth", promulgate general permission of eating all the lawful and good things of the earth, without any condition, without any restriction. But the next sentence, "and do not follow the footsteps of the Satan", shows that there are some things (related to this lawful and good eating) which are called "the footsteps of the Satan".
They are of two categories: either refraining from some food as a result of following the Satan, or eating it for the same reason. Thereafter, Allah mentions a general principle applicable to all that is done for following the Satan, that it is evil and indecency, as well as speaking against Allah what one does not know. Desisting from a food is not allowed except when Allah is pleased with such abstaining; likewise one should not audaciously use any thing without the permission of Allah.
Eating out of what is in the earth is not lawful and good unless Allah permits and allows it. And He has allowed it in this and similar verses. Also, one should ascertain that a particular thing is not forbidden or prohibited by Allah, as He says after a few verses: He has only forbidden you what dies of itself, and blood, and flesh of swine ... (2:173).
The meaning of the verse then would be as follows, and Allah knows better: Eat out of what is in the earth, from the bounties of Allah which He has created for you, as He has made them lawful and good for you; and do not leave some of them abstaining from them, because that would be evil and indecency, and you would be guilty of speaking against Allah what you do not know; it would be tantamount to making your own law against the law of Allah; and you would thus be following the footsteps of the Satan.
The verse thus shows that: First: Man has been given a general permission for unrestricted use of all that is in the earth - except the things excluded from this general rule by other proofs. Allah may forbid a thing as easily as He permits it. Second: One who abstains, without any reasonable proof, from that which Allah has made lawful, in fact promulgates his own law - which he is forbidden to do.
Third: Following the footsteps of the Satan means worshipping Allah in a way Allah has not allowed, by a method He has not approved.