Allaah (The Most High) said:

وَإِذَا سَمِعُوا مَا أُنزِلَ إِلَى الرَّسُولِ تَرَىٰ أَعْيُنَهُمْ تَفِيضُ مِنَ الدَّمْعِ مِمَّا عَرَفُوا مِنَ الْحَقِّ ۖ يَقُولُونَ رَبَّنَا آمَنَّا فَاكْتُبْنَا مَعَ الشَّاهِدِينَ

وَمَا لَنَا لَا نُؤْمِنُ بِاللَّهِ وَمَا جَاءَنَا مِنَ الْحَقِّ وَنَطْمَعُ أَن يُدْخِلَنَا رَبُّنَا مَعَ الْقَوْمِ الصَّالِحِينَ

فَأَثَابَهُمُ اللَّهُ بِمَا قَالُوا جَنَّاتٍ تَجْرِي مِن تَحْتِهَا الْأَنْهَارُ خَالِدِينَ فِيهَا ۚ وَذَٰلِكَ جَزَاءُ الْمُحْسِنِينَ

And when they (who call themselves Christians) listen to what has been sent down to the Messenger (Muhammad ), you see their eyes overflowing with tears because of the truth they have recognised. They say: “Our Lord! We believe; so write us down among the witnesses.

And why should we not believe in Allah and in that which has come to us of the truth (Islamic Monotheism)? And we wish that our Lord will admit us (in Paradise on the Day of Resurrection) along with the righteous people (Prophet Muhammad  and his Companions).”

So because of what they said, Allah rewarded them Gardens under which rivers flow (in Paradise), they will abide therein forever. Such is the reward of good-doers.

[5:83-85]