Jesus commanded the Apostles to make disciples by “teaching them to observe all things that I [Jesus] have commanded you” (Matt. 28:20). These words of Jesus establish 8 plus 1 undeniable facts.
1) Christians can and must observe all commands that Jesus gave. [Though they may stumble, they have forgiveness in repentance and prayer for forgiveness (1 John 1:7-9).]
2) Those teaching [the Apostles] can and must either individually or united know all commands to be observed.
3) These teachers can and must teach all things commanded to be observed.
4) Those being made disciples do not know all commands to be observed since they are being taught.
5) Those being made disciples can and must observe all commands since those teaching them know all commands to be observed.
6) These commands do not necessary include all spiritual things including promises of God.
7) Those being made disciples and their teachers are not commanded here to know all promises from God or all spiritual things not revealed (Deut. 29:29).
8) Teachers are not excluded from teaching for not knowing all promises and all spiritual things.
9) This is a perpetual command given first to the Apostles to teach all commands taught to them. Therefore, to teach all things is commanded for all who, individually or united, know all commands to observe.
The necessity of Jesus’ command here is shown again in that Jesus is the author of salvation to those who obey Him (Heb. 5:8-9).