Why was the phrase "we may see" used in the Holy Qur'an instead of "we have seen"?

The Quran was revealed in a clear Arabic tongue. The word "qad" (قد) in the verse: ﴿قَدْ نَرَى تَقَلُّبَ وَجْهِكَ فِي السَّمَاءِ﴾ [We have certainly seen the turning of your face toward the heaven] indicates affirmation and certainty, not reduction or doubt. "Qad" when used with a present tense verb in the Quran signifies affirmation, as in His Almighty's saying: ﴿قَدْ يَعْلَمُ اللَّهُ الَّذِينَ يَتَسَلَّلُونَ مِنْكُمْ لِوَاذًا﴾ [Allah certainly knows those of you who slip away, concealing themselves]. It functions similarly to "inna" (إنَّ) when used with nouns for affirmation.