إِنَّمَا نَعُدُّ لَهُمْ عَدًّا
"We are but counting for them a count down." - 19:84
This verse means: "Do not be impatient about their punishment because it is going to befall upon them in any case - and very soon. We have allowed them a fixed term in this world and that term is about to end. Then will come their retribution." نَعُدُّ لَهُمْ means: "We are counting for them, i.e. they do not have control on anything. Their days are numbered and We keep a count of every moment of their life and everything they do."
Once Ma'mun Rashid read Surah Maryam. Upon reading this particular verse, he desired that Ibn Simak, one of the Islamic scholars sitting in that meeting with him, to say something on it. Thereupon Ibn Simak submitted that when our breaths are numbered and their number cannot be enhanced, they will soon come to an end. The same notion is reflected in the following poetic verse:
حیاتک انفاس تعد فکلّمَا مضی نفس منک انتقصت بہ جزء اً
That is, the breaths of your lifer are counted. With every passing breath, your life gets reduced to that extent.
It is said that during one span of twenty-four hours, one breathes twenty-four thousand times. (Qurtubi)
The following stanza explores the same context:
و کیف یفرح بالدّنیاو لذّتھا فتی یُعَدّ علیہ اللفظ و النّفس
That is, how can one be so engrossed and relaxed with the worldly pleasures, while his words and breaths are being counted. (Ruh)