(… الْهُدَى …) (…guidance …): It is the straight path:
وَأَنَّ هَٰذَا صِرَاطِي مُسْتَقِيمًا فَاتَّبِعُوهُ ۖ وَلَا تَتَّبِعُوا السُّبُلَ فَتَفَرَّقَ بِكُمْ عَن سَبِيلِهِ
(And, [moreover], this is My path, which is straight, so follow it; and do not follow [other] ways, for you will be separated from His way.) (Al-An’am: 153)
The path which leads to the aim which is gaining the satisfaction of Allah (swt), it is Allah’s (swt) Book, the Sunnah of the Prophet (saws), his commands, actions and behavior. So, whoever opposes the Prophet (saws) and follows other than what were mentioned, he will be driven into bad destiny in the day of judgement.