The work of Satan is to adorn falsehood. Satan cannot give you strength and victory. Instead, he can only whisper and deceive.
(وَإِذْ زَيَّنَ…) (And [remember] when Satan made their deeds pleasing to them,): It means he tempted them.
(…وَقَالَ لَا غَالِبَ لَكُمُ الْيَوْمَ مِنَ النَّاسِ وَإِنِّي جَارٌ لَّكُمْ…ۖ) (And said, ‘No one can overcome you today from among the people, and indeed, I am your protector.’): This is because Satan cannot use anything other than words to deceive.
وَقَالَ الشَّيْطَانُ لَمَّا قُضِيَ الْأَمْرُ إِنَّ اللَّهَ وَعَدَكُمْ وَعْدَ الْحَقِّ وَوَعَدتُّكُمْ فَأَخْلَفْتُكُمْ ۖ وَمَا كَانَ لِيَ عَلَيْكُم مِّن سُلْطَانٍ إِلَّا أَن دَعَوْتُكُمْ فَاسْتَجَبْتُمْ لِي ۖ فَلَا تَلُومُونِي وَلُومُوا أَنفُسَكُم ۖ مَّا أَنَا بِمُصْرِخِكُمْ وَمَا أَنتُم بِمُصْرِخِيَّ ۖ إِنِّي كَفَرْتُ بِمَا أَشْرَكْتُمُونِ مِن قَبْلُ
(And Satan will say when the matter has been concluded, ‘Indeed, Allah had promised you the promise of truth. And I promised you, but I betrayed you. But I had no authority over you except that I invited you, and you responded to me. So do not blame me; but blame yourselves. I cannot be called to your aid, nor can you be called to my aid. Indeed, I deny your association of me [with Allah] before.’ Indeed, for the wrongdoers is a painful punishment) (Ibrahim: 22)
It means Satan said: “I promised you only with words”.
(…وَإِنِّي جَارٌ لَّكُمْ… ۖ) (And indeed, I am your protector.): Satan promised them: ‘I am with you, supporting you and strengthening you. I will be by your side in this battle.’
(…فَلَمَّا تَرَاءَتِ الْفِئَتَانِ…) (But when the two armies sighted each other,): When the army of the Prophet (saws) became positioned at Badr, facing the polytheists, where they could see each other directly. The situation intensified, and the battle commenced.
(…نَكَصَ عَلَىٰ عَقِبَيْهِ…) (He turned on his heels): At this point, Satan fled away.
(…وَقَالَ إِنِّي بَرِيءٌ مِّنكُمْ إِنِّي أَرَىٰ مَا لَا تَرَوْنَ إِنِّي أَخَافُ اللَّهَ ۚ وَاللَّهُ شَدِيدُ الْعِقَابِ): (And said, ‘Indeed, I am disassociated from you. Indeed, I see what you do not see; indeed I fear Allah. And Allah is severe in penalty.’): Satan, or the devil, is a creature made of fire. As mentioned before, Allah created jinns, humans, and angels. Not everything that we cannot see does not exist. Many living creatures like germs and bacteria exist but are invisible to us. The term “Satan” is used for any evil or corrupt being, whether from the jinn or humans. Here, we refer to the evil one among the jinns who was cast down to Earth, the one who said: “By Your might” (Sad: 82) which means ‘by Your power and by Your Self-sufficiency from Your creation’, which is clearly indicated in this verse: “indeed I fear Allah. And Allah is severe in penalty.”
A question may arise: As Satan fears Allah (swt), why did he continue in his wrongdoing? And why will he enter the Hellfire? The answer is: Satan showed arrogance at the moment when Allah (swt) commanded him to bow to Adam (PBUH), and thus he was expelled from Allah’s mercy. So, although he knows about Allah’s punishment and fears it, he rejected Allah’s decree. His knowledge alone won’t benefit him without having true piety towards Allah and obeying His commands.