be attentive to the call of prayer (Allahu Akbar).

Once he hears the call Allahu Akbar one should not delay the prayer instead he should attend to it

and then he can resume any worldly activity.

Because the meeting with Allah will aid you with your worldly activities. What we call the blessed time.

It is important that one is attentive to this matter

in that they should not ignore Allah's call to him.

If my father calls me and I didn't go to him, he would be upset with me. And so Allah says in a Qudsi hadith

Whoever responds when I call him I will respond to him when he calls me.