"Then the truth occurred," meaning: it became manifest.
Al-Kalbi said:
And the magicians said to one another: "If this were magic, our ropes and staffs would have remained."
﴿فَوَقع الْحق﴾ فَظَهَرَ.
قَالَ الْكَلْبِيُّ:
وَقَالَ السَّحَرَةُ بَعْضُهُمْ لِبَعْضٍ: لَوْ كَانَ هَذَا سحرًا لبقيت حبالنا وعصينا.