Al-A'raf - 7:21

وَقَاسَمَهُمَا إِنِّي لَكُمَا لَمِنَ النَّاصِحِينَ
[7:21]
And he swore to them both: Most surely I am a sincere adviser to you.
And he swore to them both, that he was their sincere adviser.
And he swore unto them (saying): Lo! I am a sincere adviser unto you.