'Theirs' in the Bible

"Blessed are the poor in spirit, for theirs is the Kingdom of Heaven.

Blessed are those who have been persecuted for righteousness' sake, for theirs is the Kingdom of Heaven.

to the assembly of God which is at Corinth; those who are sanctified in Christ Jesus, called to be saints, with all who call on the name of our Lord Jesus Christ in every place, both theirs and ours:

But they will proceed no further. For their folly will be evident to all men, as theirs also came to be.

For men indeed swear by a greater one, and in every dispute of theirs the oath is final for confirmation.