Those who worship shaytan ...

• Based on the verses of Surah Yaseen

60) أَلَمْ أَعْهَدْ إِلَيْكُمْ يَا بَنِي آدَمَ أَن لَّا تَعْبُدُوا الشَّيْطَانَ  إِنَّهُ لَكُمْ عَدُوٌّ مُّبِينٌ 
Did I not enjoin upon you, O children of Adam, that you not worship Satan – [for] indeed, he is to you a clear enemy .
أَعْهَدْ is a binding promise/oath, an agreement and contract.
All humans have solemnly pledged to Allah to devoutedly and committedly worship Allah.
Before the creation of the universe, Allah made human souls and in the valley of "alast", Allah asked our souls if we recognize Him as our Creator, Sustainer and Master. We replied in the affirmative. Although we do not recall this event but it resonates to day today in our souls. This is why whenever a person hears the Qur'an (speech of Allah), it touches and softens our heart. It's innate in our psyche to incline towards, find great solace and satisfaction in Allah and His Book (Qur'an).

تَعْبُدُوا is from عبادة, which means to worship. Worship is to obey unconditonally with love and humility, to dutifully submit with respect and adoration, to have utmost conviction and reliance. Allah is deserving of our worship because He is our Creator.
أَن لَّا تَعْبُدُوا الشَّيْطَانَ Allah has prohibited us from worshiping the Shaytan because Shaytan is our enemy. Shaytan encourages debauchery and  immorality. He plagues the mind withe fear, negative thoughts, depression, arrogance, greed and lust. He confuses us over the Divinity and Lordship of Allah. He makes all evil, sinister, vile and perverse practices, behaviour, clothes, words and food appealing to us. He wants to destroy and ruin us. 
To know more about the tricks and traps of of Shaytan, see: Exposing Shaytan

إِنَّهُ لَكُمْ عَدُوٌّ مُّبِي Shaytan is an open enemy. There is nothing covert about his hostility and hatred towards all human beings. He is adamant in ruining our lives by making us commit sins excessively and by dragging us to Hellfire with him.

بَنِي آدَمَ  Allah calls us the 'children of Adam'. We are the descendants of the first man on earth and a noble Prophet of Allah. Adam (a.s) received knowledge from Allah; he lived his life as the vicegerent of Allah. Angels and Shaytan were commanded to prostrate to him. So as his children, we must sustain his legacy and follow his good example.

61) وَأَنِ اعْبُدُونِي  هَـٰذَا صِرَاطٌ مُّسْتَقِيم 

And that you worship [only] Me?  This is a straight path. 

صِرَاطٌ مُّسْتَقِيمٌ - the path of faith, righteousness, justice, compassion and Paradise. Worshiping Allah guides one to sound faith and prompts righteousness. Worshipping Allah generates justice and compassion in society and leads people to Paradise.

62) وَلَقَدْ أَضَلَّ مِنكُمْ جِبِلًّا كَثِيرًا  أَفَلَمْ تَكُونُوا تَعْقِلُونَ 
And he had already led astray from among you much of creation, so did you not use reason?
Shaytan has become successful in misleading a vast majority of the people into corruption, cruelty, delusion and destruction.
Check yourself: Do you worship Allah or is Shaytan always successful in getting you to delay and miss your Salah? Are your actions based upon the Sunnah or has Shaytan convinced you to do whatever you feel like doing or whatever your friends want to do? Do your actions bring a positive reaction or are you a trouble maker everywhere you go?
أَفَلَمْ تَكُونُوا تَعْقِلُونَ  - so did you not use reason? Always use your common sense. Do my actions make any sense? Am I behaving reasonably? Am I pleasing Allah or Shaytan? Am I obeying Allah or Shaytan? Are my choices leading me to Paradise or Hellfire?

63) هَـٰذِهِ جَهَنَّمُ الَّتِي كُنتُمْ تُوعَدُونَ 
This is the Hellfire which you were promised.
 Those who worship and obey Shaytan are promised Hellfire. Instead of loving Allah and taking Him as their God, they followed Shaytan who corrupted them so there is no other recourse for them except Hellfire.

64) اصْلَوْهَا الْيَوْمَ بِمَا كُنتُمْ تَكْفُرُونَ 
[Enter to] burn therein today for what you used to deny.
تَكْفُرُونَ - The people who disbelieved in Allah and refused to worship him
اصْلَوْهَا - The disbelievers will enter to burn and roast in Hellfire. Imagine an oven that heats and cooks food thoroughly. Imagine when potatoes are boiled/baked, they become soft until their skin peels off easily like wet/light paper or tissue.
In hellfire, people will burn until their skins peel off from their flesh. Then new skins will be given to them and they will be roasted until that skin become brittle and it sheds. Again they will receive new skins which will burn so severely that it too peels off. This process of the skin searing and intensely baking in the igneous fire of Hell will persist for all eternity. Just look at the intensity and ferocity with which fire of this world burns. Can any person survive the excruciating agony and shooting pain of Hellfire which is 69 times more dreadful than the blazing fire of Hell?

65) الْيَوْمَ نَخْتِمُ عَلَىٰ أَفْوَاهِهِمْ وَتُكَلِّمُنَا أَيْدِيهِمْ وَتَشْهَدُ أَرْجُلُهُم بِمَا كَانُوا يَكْسِبُونَ - That Day, We will seal over their mouths, and their hands will speak to Us, and their feet will testify about what they used to earn.
Allah will seal our mouth on the Day of Judgment. The sinners and the disobedient of Allah will be hushed from wrongfully giving excuses and and lies in their defense. Our hands and feet will speak to Allah, and give truthful evidence of our actions.
Our body and our limbs are the property of Allah. He trusted us with hands and feet temporarily and on the Day of Judgment, He will question us regarding their use. Every thing we do in our life, has a positive or negative value and a price. With our hands and feet we can either worship of Allah and earn reward or worship Shaytan and earn sins. Whatever we choose to do with our body, which a trust from Allah, Allah will see it and recompense us for it.

66) وَلَوْ نَشَاءُ لَطَمَسْنَا عَلَىٰ أَعْيُنِهِمْ فَاسْتَبَقُوا الصِّرَاطَ فَأَنَّىٰ يُبْصِرُونَ - And if We willed, We could have obliterated their eyes, and they would race to [find] the path, and how could they see?
Like all our other faculties, our eyes are a blessing from Allah. To use any of our sense to disobey Allah is a betrayal and treachery of the worst kind. How can we disobey Allah using the very limbs and senses which Allah gave us? How can we disobey Allah when we receive nourishment and health from the food that He has created? How can we disobey Allah when we live in His lands and breathe His air?
Just as Allah has enabled us to see from our eyes, Allah has also guided us to see things from our heart, that is, to obtain a deeper and wiser understanding of things. There is more to life and the world around us than what meets the eyes at surface level. Through the Qur'an, Allah has guided us to decipher many realities and shown us the straight path.

67) وَلَوْ نَشَاءُ لَمَسَخْنَاهُمْ عَلَىٰ مَكَانَتِهِمْ فَمَا اسْتَطَاعُوا مُضِيًّا وَلَا يَرْجِعُونَ -  And if We willed, We could have deformed them, [paralyzing them] in their places so they would not be able to proceed, nor could they return.
Before commiting any sin, just imagine if Allah deformed you or paralyzed you in the state. As you sneaked out of the house to smoke, or entered an online chat room to date, Allah deformed your hands so you could not hold the cigarette or type. What if our faces were disfigured every time we lied, backbit or listened to music? What if we were crippled every time we hit someone or transfixed as we ate unlawful foods? Youth, health, strength, intellect and spare time are some of the greatest blessings of Allah. Don't think that because you are young, brave and beautiful you can do anything you want. Or that so long as you can hide your sins from your parents, it's okay. Really think about the control and authority Allah has on you and use all the blessings Allah gave you to do good deeds. Take lesson from the people around you lest you sin and suffer terminally as they do without any cure or relief in sight. How many people smoked and now are going to several heart surgeries and lung transplants. How many people develop illicit relations with non-mahram only to be afflicted with the angst of AIDS and HIV. So be very careful and remain obedient to Allah. Worship Allah and avoid the whispers of Shaytan and inshaAllah this is best for you in both worlds.

68) وَمَن نُّعَمِّرْهُ نُنَكِّسْهُ فِي الْخَلْقِ أَفَلَا يَعْقِلُونَ - And he to whom We grant long life We reverse in creation; so will they not understand?
Don't wait for old age till you change. Make an effort now and come close to Allah immediately. Old age is filled with many hardships. A elderly person looses all his physical strength and beauty, his intellect and even his temper. In old age, a person is like a young child - very feeble, insensible and insecure. Avail all your time and energies now, don't sell yourself to Shaytan because he will never let you free when you are old. If your habits are immoral today, there is no guarantee, you will be able to reform yourself in old age. Understand that life is not forever. Humans exist for a very limited time on earth so don't postpone the worship of Allah, dedicate every second of your life now and till death in the worship of Allah.