You may be mixing up Christ’s gift of sacramental authority with the rest of Christ’s teachings.
The Apostles are those who were given special authority and responsibility by Christ. Only they - and their descendants - were and are given authority by Christ to enact certain of the sacraments: to absolve sinners and re-enact the Eucharist, to ordain Priests and ministers.
We all must love God and our neighbor. We must all follow the commandments. But (for instance) only Priests can celebrate the Eucharist or absolve sins.
There are exceptions: laymen have the ability to carry out some sacraments - notably Marriage and Baptism, as long as (IIRC) they are carried out in the name of the Father, and of the Son, and of the Holy Spirit.
Where is that in the New Testament? I know of only one epistle where the order of the authority of the church was mentioned. Nothing of the sort you mention is written in that epistle. Christ alone can forgive (absolve) sin. No man is capable of such a thing.