Al-Baqarah - 2:249

فَلَمَّا فَصَلَ طَالُوتُ بِالْجُنُودِ قَالَ إِنَّ اللّهَ مُبْتَلِيكُم بِنَهَرٍ فَمَن شَرِبَ مِنْهُ فَلَيْسَ مِنِّي وَمَن لَّمْ يَطْعَمْهُ فَإِنَّهُ مِنِّي إِلاَّ مَنِ اغْتَرَفَ غُرْفَةً بِيَدِهِ فَشَرِبُواْ مِنْهُ إِلاَّ قَلِيلاً مِّنْهُمْ فَلَمَّا جَاوَزَهُ هُوَ وَالَّذِينَ آمَنُواْ مَعَهُ قَالُواْ لاَ طَاقَةَ لَنَا الْيَوْمَ بِجَالُوتَ وَجُنودِهِ قَالَ الَّذِينَ يَظُنُّونَ أَنَّهُم مُّلاَقُو اللّهِ كَم مِّن فِئَةٍ قَلِيلَةٍ غَلَبَتْ فِئَةً كَثِيرَةً بِإِذْنِ اللّهِ وَاللّهُ مَعَ الصَّابِرِينَ
[2:249]
So when Talut departed with the forces, he said: Surely Allah will try you with a river; whoever then drinks from it, he is not of me, and whoever does not taste of it, he is surely of me, except he who takes with his hand as much of it as fills the hand; but with the exception of a few of them they drank from it. So when he had crossed it, he and those who believed with him, they said: We have today no power against Jalut and his forces. Those who were sure that they would meet their Lord said: How often has a small party vanquished a numerous host by Allah's permission, and Allah is with the patient.
When Talut set forth with the armies, he said: "Allah will test you at the stream: if any drinks of its water, He goes not with my army: Only those who taste not of it go with me: A mere sip out of the hand is excused." but they all drank of it, except a few. When they crossed the river,- He and the faithful ones with him,- they said: "This day We cannot cope with Goliath and his forces." but those who were convinced that they must meet Allah, said: "How oft, by Allah's will, Hath a small force vanquished a big one? Allah is with those who steadfastly persevere."
And when Saul set out with the army, he said: Lo! Allah will try you by (the ordeal of) a river. Whosoever therefore drinketh thereof he is not of me, and whosoever tasteth it not he is of me, save him who taketh (thereof) in the hollow of his hand. But they drank thereof, all save a few of them. And after he had crossed (the river), he and those who believed with him, they said: We have no power this day against Goliath and his hosts. But those who knew that they would meet Allah exclaimed: How many a little company hath overcome a mighty host by Allah's leave! Allah is with the steadfast.