The ruling on one who begins a voluntary prayer and then the iqamah is called

Question:
A man entered the mosque and began a voluntary prayer, but the iqamah was called before he bowed. Should he conclude the prayer, or complete it quickly?

Answer:
In any case, if one begins a voluntary prayer and then the iqamah is called, he must discontinue it, because the obligatory prayer is more important. The Prophet (peace and blessings be upon him) said: It was narrated by Muslim in the Sahih.
It is obligatory for one who has entered a voluntary prayer, whether it is the greeting of the mosque or a regular voluntary prayer, and then the iqamah is called, to discontinue this voluntary prayer. That is, he intends to discontinue it and engages in the obligatory prayer with the imam, unless he is at the end of it and has already bowed the second bow. In that case, the matter is broad. If he is at the end of it, the end is not a full unit of prayer, but rather a small amount that does not prevent him from following the imam and catching up with the imam in the opening takbir. So if the iqamah is called while he is in the second bow, or in the final prostration, or in the tashahhud, he completes it and catches up with the imam, because the amount of prayer remaining is one unit. If he has bowed the second bow, less than one unit remains; so he completes it, then joins the imam.

Question : Is this in the first unit?

Answer: He discontinues it in the first unit, or in the second. He discontinues it before the bow. He discontinues it. This is what should be done due to the generality of the hadiths and the minimum of prayer is one unit. So if one unit remains for him, he discontinues it.