Them that labour among you (tou kopiwnta en umin). Old word for toil even if weary. And are over you in the Lord (kai proistamenou umwn en Kuriwi). Same article with this participle. Literally, those who stand in front of you, your leaders in the Lord, the presbyters or bishops and deacons. Get acquainted with them and follow them. And admonish you (kai nouqetounta uma). Old verb from nouqeth and this from nou (mind) and tiqhmi, to put. Putting sense into the heads of people. A thankless, but a necessary, task. The same article connects all three participles, different functions of the same leaders in the church.