Witnesses

After the great commission, Luke records that for forty days Jesus showed Himself alive to many witnesses and spoke to them about the kingdom of God.

"To whom also he shewed himself alive after his passion [crucifixion] by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God:" - Acts 1:3 

Jesus did His part: Jesus died for our sins, was buried, and on the third day rose again. Then for forty days He witnessed of His resurrection and talked about the kingdom of God. (1 Corinthians 15:3-7, Acts 1:3).

Now we do our part: We repent of our sins, are baptized in the name of Jesus for the remission of sins, and we receive the gift of His Spirit. (Acts 2:38). This is our testimony. We witness of our new life in Jesus and we talk about the kingdom of God. (John 3:5).

"To wit, that God was in Christ, reconciling the world unto himself, not imputing their trespasses unto them; and hath committed unto us the word of reconciliation." - 2 Corinthians 5:19 

"Now then we are ambassadors for Christ, as though God did beseech you by us: we pray you in Christ's stead, be ye reconciled to God." - 2 Corinthians 5:20

"Then said Jesus to them again, Peace be unto you: as my Father hath sent me, even so send I you." - John 20:21 

"But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth." - Acts 1:8 

We are witnesses to the world of what Jesus did for us, and in us. Finally, at the end, this is how we defeat the devil.

We overcome the accuser of our brethren (the devil) by the blood of the Lamb – the death, burial, and resurrection of Jesus - and by the word of our testimony – our repentance, baptism in the name of Jesus, and our infilling of the Holy Ghost. 

"And they overcame him by the blood of the Lamb, and by the word of their testimony; and they loved not their lives unto the death." - Revelation 12:11