The Apostle wants you to know that you’ve been sanctified, preserved and called. He says, "mercy unto you, and peace, and love, be multiplied" if you have this knowledge.
In verse 3 he says it was needful for me to write unto you, and exhort you that ye should earnestly contend for the faith which was once delivered unto the saints.
Why he’s writing is because "certain men crept in unawares, who were before of old ordained to this condemnation, ungodly men, turning the grace of our God into lasciviousness, and denying the only Lord God, and our Lord Jesus Christ" Jude 1:4. These evil men were teaching otherwise, like is the situation these days, that some think only a few have been called, anointed, or chosen to preach, but our salvation is a common salvation my friend - we’ve all been called, and teaching otherwise is denying or resisting what Jesus came here to do and to serve.
Paul says, "Nevertheless, whereto we have already attained, let us walk by the same rule, let us mind the same thing. Brethren, be followers together of me, and mark them which walk so as ye have us for an ensample. (For many walk, of whom I have told you often, and now tell you even weeping, that they are the enemies of the cross of Christ: Whose end is destruction, whose God is their belly, and whose glory is in their shame, who mind earthly things.) Philippians 3:16-19
He says, "There is one body, and one Spirit, even as ye are called in one hope of your calling; One Lord, one faith, one baptism, One God and Father of all, who is above all, and through all, and in you all. But unto every one of us is given grace according to the measure of the gift of Christ." Ephesians 4:4-7.
In the great commission Jesus said, "All power is given unto me in heaven and in earth. Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, even unto the end of the world. Amen." Matthew 28:18-20.
Jesus wants his believers to know that they’ve one hope of calling; and that every one of us is given grace according to the measure of the gift of Christ, and no one person should detect what he thinks you should do.
But he sanctified you, preserved you, and called you for this one purpose; that you should earnestly contend for the faith - we all share this common salvation and purpose.
Don’t allow ungodly men to robe you of this common salvation, and mission. Let us walk by the same rule, let us mind the same thing. and be ye followers of that which is good and godly, the perfect will of God for you. Not witnessing will make a believers worse than infidels or enemies of the cross of Christ.
But this know that when we received him, there was only one hope of your calling; one faith and one baptism. Each one of us is given grace according to the measure of the gift of Christ to testify or bear witness of his mercy, and peace, and love. Jesus said to the man delivered, "Go home to thy friends, and tell them how great things the Lord hath done for thee, and hath had compassion on thee." Mark 5:19. Preaching is our common denominator.
God bless you,