Read Surah Al-Kafirun

أنها تقع للمضارع الذي لم يقع سواء كان في غاية القرب من الحال...

It applies to the imperfect tense that has not occurred, whether it is near or far from the current situation, as I mentioned earlier in Surah Al-Baqarah at {walan taf'aloo} [Al-Baqarah: 24]. Our utterance of this statement can hardly be realized until time passes and it becomes future tense. Therefore, it is expressed with 'la' instead of 'ma' as a sign that Allah will keep him on the straight path and they will not attain it - a sign of prophethood. Since their objects of worship included things that are unintelligible, and the intention was to belittle everything they worshipped besides Allah, it is expressed with 'ma' and said: {ma ta'budun} meaning what you worship now and in the future, besides Allah, from visible and invisible objects of worship, in any form of worship, in secret or openly, because it is not worthy of worship in any way. Since he began with what is more deserving of being mentioned first, which is the declaration of innocence from polytheism and purification from the evil of slander, as it is a means of warding off corruption, he conveyed it in a way that is true to his situation, may Allah's peace be upon him. They used to worship Allah while associating partners with Him, and worship with polytheism is not considered valid in any way. He negated their worship of Him in general terms, using a noun that implies permanence, not in a way that negates every small and large amount of it, since the action is indefinite in the context of negation. So, he said: {wa la antum 'abidun} meaning worship that is considered valid, to the extent that it can be a lasting attribute.