Today's verse

بِسْمِ اللّهِ الرَّحْمَنِ الرَّحِيْم

Chapter 109
ﺳﻮﺭﺓ ﺍﻟﻜﺎﻓﺮﻭﻥ
Sūrat al-Kāfirūn
The Disbelievers

Verse 3

Arabic

ﻭَﻟَﺎ ﺃَﻧﺘُﻢْ ﻋَﺎﺑِﺪُﻭﻥَ ﻣَﺎ ﺃَﻋْﺒُﺪُ

Meaning:

3. “Nor do you worship Whom I worship

Transliteration:

Wa laa antum 'aabiduuna maa a'abud
Tafsir:

Imam Ibn Kathir did the tafsir of verses 3-5 together.

Please read these comments on verse 2&3, I'll bring us Imam's tafsir after verse 5  إن شاء الله ‏
Comments on Verse 2

لَا أَعْبُدُ مَا تَعْبُدُونَ
 [Al-Kaafiroon : 2]

(109:2) I do not worship those that you worship *2

*2) This includes aII those deities whom the disbelievers and the polytheists have been, and are still, worshipping everywhere in the world, whether they are the angels, the jinn, prophets, saints, spirits of the living or dead men, or the sun, the moon, stars, animals, trees, rivers, idols and imaginary gods and goddesses. One may say that the pagans of Arabia acknowledged Allah also as a Deity and the other pagans of the world also have never disacknowledged Allah as a Deity till today. As for the followers of the earlier scriptures, they also acknowledge Allah alone as the real Deity. How then can it be correct to exonerate oneself froth the worship of all the deities of all those people, without' exception, when AIIah too is included among them? The answer is that if AIlah is worshipped along with others regarding Him as a Deity among other deities, the believer in Tauhid will inevitably express his inmunity from this worship, for in his sight Allah is oat a Deity out of a collection of deities, but He alone is the real Deity, and the worship of the collection of deities is no worship of Allah, although worship of Allah also is included in it. The Qur'an has clearly stated that Allah's worship is only that which does not have any tinge of the worship of another and in which man makes his worship exclusively Allah's. "And the only Command they were given, was to worship Allah, making their religion sincerely His, turning all their attention towards Him." (Al-Bayyinah: S).

This subject has been explained at many places in the Qur'an forcefully; for example, see An-Nisa': 145-146, AI-A`raf :29, AzZumar: 2, 3, 11, 14, 15, A1-Mu'min: 14, 64-66. It has been further explained in a Hadith Qudsi (i.e. Divine Word revealed through the mouth of the Prophet) in which the messenger of Allah says: "Allah says: I am Self-Sufficient of the association of every associate most of all. Whoever performed an act in which he associated another also with Me, 1 am free of it, and the entire act is for him who was associated."(Muslim, Musnad Ahmad, Ibn Majah).

Thus, acknowledging Allah as one of the two, three or many gods and serving and worshipping others along with Him is, in fact, the real kufr, declaration of immunity from which is the object of this Surah. 
109:3) neither do you worship Him Whom I worship; *3

When it was said: La antum 'abiduna ma a `bud, it meant: "You are not worshippers of the Deity who has the attributes of the Deity whom I worship." And this is the real point on the basis of which the religion of the Prophet Muhammad (upon whom be Allah's peace and blessings) is absolutely distinguish-ed from the religions of all kinds of disbelievers, besides the deniers of God, for his God is utterly different from the God of all of them. The God of some of them is such that He stood in need of rest on the seventh day after having created the world in six days, Who is not God of the universe but God of Israel, Who stands in a special relationship to the people of one particular race, which is not shared by other men, Who wrestles with the Prophet Jacob and cannot throw him, Who has also a son, named Ezra. The God of some others is father of an only son, called Jesus Christ, and He causes His son to be crucified in order to make him an atonement for the sins of others. The God of some has wife and children, but begets only daughters. The God of some assumes human form and shape and living in a human body on the earth works like men. The God of some is merely an Essence, or Cause of causes, or the First Cause, Who after giving the system of the universe the initial push is sitting aside unconcerned, the universe is working by itself according to some relentless laws, and now He and man have nothing to do with each other. In short, even the unbelievers who acknowledge God do not, in fact, acknowledge the God, Who is the Creator, . Master, Disposer, Administrator and Ruler of the entire universe, Who has not only set the system of the universe but is running and controlling it by Himself every moment, Who is above every defect, fault, weakness and error, Who is free from every similitude, every physical limitation, every likeness, Who is Self-Sufficient of every companion and associate, Who has no partner in His Being, attributes, powers and entitlement to worship, Who is far too Holy that He should have children, or should take some one for a son, or should have an exclusive relationship with a community or race, Who is directly related to each individual creature of His as His Providence, Sustainer and Guardian, Who hears the prayers and answers them, Who alone possesses all the powers to give Iife and death, to cause profit and loss, and to make and mar destinies, Who not only sustains His creatures but also guides each according to its nature and need, Who is not only our God Whom we worship but also enjoins commands and prohibitions through His Prophets and His Books, which we have to obey, before Whom we are accountable for our deeds, Who will resurrect us after death, call us to account and reward and punish us accordingly. No one in the world except for Muhammad (upon whom be Allah's peace and blessings) and his followers, is worshipping the God with these attributes. If at alI some others also are worshipping God, they are not worshipping the real and true God but the God who is their self-invented, imaginary God.