The Catechism in Questions & Answers

450. When was the Apostle ministry occupied again?

The Apostle ministry was once again personally occupied in accordance with God’s will when the time for the final gathering and preparation of the bridal congregation for the return of Christ had come: as of the year 1832 the Apostle ministry was once again occupied.
Apostles are thus active at the start of the church of Christ and in the time before the return of Christ in order to prepare the bridal congregation.

Bridal congregation: see Questions 562. et seq.

The term ‘personal occupation’ of the Apostle ministry is intended to express that there are bearers of the Apostle ministry. They have been called to this ministry and exercise it in the mind and Spirit of Jesus Christ.