'Only Son' in the Bible

O daughter of my people, put on sackcloth, and wallow in ashes; make mourning for yourself, as for an only son, most bitter weeping; for the ravager shall suddenly come on us.

And I will turn your feast into mourning, and all your songs into weeping; and I will bring up sackcloth on all loins, and baldness on every head. And I will make it like the mourning of an only son, and the end of it like a bitter day.

And I will pour on the house of David, and on the people of Jerusalem, the spirit of grace and of prayers. And they shall look on Me whom they have pierced, and they shall mourn for Him, as one mourns for his only son, and shall be bitter over Him, as the bitterness over the first-born.

And drawing near the gate of the city, even behold, one having died was being carried out, an only son of his mother, and she was a widow. And a considerable crowd of the city was with her.