You might say that the field of preaching enlarged from a “pond ” of Jews to an“ ocean ” of mankind.
وَهٰذَا عَنَى أَنَّهُ عَلَى ٱلْمَسِيحِيِّينَ أَنْ يَذْهَبُوا وَيَكْرِزُوا لِكُلِّ ٱلنَّاسِ حَوْلَ ٱلْعَالَمِ .‏