Heb. 7:12

God changed the law.

If God would not have changed the law, Christ could not be our High Priest (Heb. 7:11-14; 8:4). Anyone claiming that the Moral or Mosaic Laws are authoritative cannot claim Jesus as his High Priest.

Gal. 6:2

We must fulfill the law of Christ.

God's covenant with us is mediated by Christ (Heb. 8:6). It is composed of laws (Heb. 8:10). We must obey Christ to be saved (Heb. 5:9).

Jn. 12:48

Jesus' words (Gal. 6:2 the law of Christ; 2 Jn. 9 the doctrine of Christ) will judge man (cf. Ja. 1:25; 2:12).

People who receive the word of Jesus preached through the apostles repent and are baptized in the name of Jesus Christ for the remission of their sins (Acts 2:38) to be saved (Acts 2:40-41).

1 Cor. 9:21

We are under law toward Christ.

2 Jn. 9

The doctrine of Christ sets forth Christ's law (cf. Gal. 6:2; Ja. 1:25).

We must obey the gospel of Christ (Heb. 5:9; 2 Th. 1:8).

Ja. 1:25

The perfect law of liberty is the law of Christ.

Liberty and perfection are in Christ (Gal. 2:4; Col. 1:28). Therefore Christ's law (1 Cor. 9:21; Gal. 6:2) is the perfect law of liberty.

Jesus said that we will be judged by His words (Jn. 12:48). And, James said that we will be judged by the law of liberty (Ja. 1:25; 2:12). Therefore, the words of Christ (spoken by Himself or through His apostles) constitute the law of liberty (cf. Gal. 6:2; 2 Jn. 9). The law of Christ and the law of liberty are synonymous.