It has been narrated on the authority of Abu Sa`id al-Khudri that the Messenger of Allah (ﷺ) said (to him):

Abu Sa`id, whoever cheerfully accepts Allah as his Lord, Islam as his religion and Muhammad as his Messenger is necessarily entitled to enter Paradise. He (Abu Sa`id) wondered at it and said: Messenger of Allah, repeat it for me. He (the Messenger of Allah) did that and said: There is another act which elevates the position of a man in Paradise to a grade one hundred (higher), and the elevation between one grade and the other is equal to the height of the heaven from the earth. He (Abu Sa`id) said: What is that act? He replied: Jihad in the way of Allah! Jihad in the way of Allah!

حَدَّثَنَا سَعِيدُ بْنُ مَنْصُورٍ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ وَهْبٍ، حَدَّثَنِي أَبُو هَانِئٍ الْخَوْلاَنِيُّ، عَنْ أَبِي عَبْدِ الرَّحْمَنِ الْحُبُلِيِّ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ يَا أَبَا سَعِيدٍ مَنْ رَضِيَ بِاللَّهِ رَبًّا وَبِالإِسْلاَمِ دِينًا وَبِمُحَمَّدٍ نَبِيًّا وَجَبَتْ لَهُ الْجَنَّةُ ‏"‏ ‏.‏ فَعَجِبَ لَهَا أَبُو سَعِيدٍ فَقَالَ أَعِدْهَا عَلَىَّ يَا رَسُولَ اللَّهِ فَفَعَلَ ثُمَّ قَالَ ‏"‏ وَأُخْرَى يُرْفَعُ بِهَا الْعَبْدُ مِائَةَ دَرَجَةٍ فِي الْجَنَّةِ مَا بَيْنَ كُلِّ دَرَجَتَيْنِ كَمَا بَيْنَ السَّمَاءِ وَالأَرْضِ ‏"‏ ‏.‏ قَالَ وَمَا هِيَ يَا رَسُولَ اللَّهِ قَالَ ‏"‏ الْجِهَادُ فِي سَبِيلِ اللَّهِ الْجِهَادُ فِي سَبِيلِ اللَّهِ ‏"‏ ‏.‏