The letter (أَ) is interrogative tool.(اداة الاستفهام)
1) أ+ يَرْبِطُ
2) يربط est le verbe : رَبَطَ conjugued in present = tie the sheep by the rope
The proposal seemed to shock the little prince
Attach it? What a strange idea!
But if you do not tie him, he will go anywhere,
and he will be lost. "