I'd like to give my understanding and opinion concerning evangelism, including why it has become ineffective among us. I realize my opinion is not a popular one and will probably be sneered at and rejected, but that is OK, I am more used to being considered as a 'deplorable' than an 'elite'.
By the proper principles of study of Scripture for the purpose of application, what we call "The Great Commission" was actually intended for the immediate audience.
However, evangelism is also an important function of the Body, as well as, in a different way, for each member of the Body.
The first part may be illustrated by what Paul said in
Ephesians 4:11-16 English Standard Version (ESV)
11 And he gave the apostles, the prophets, the evangelists, the shepherds and teachers, 12 to equip the saints for the work of ministry, for building up the body of Christ, 13 until we all attain to the unity of the faith and of the knowledge of the Son of God, to mature manhood, to the measure of the stature of the fullness of Christ, 14 so that we may no longer be children, tossed to and fro by the waves and carried about by every wind of doctrine, by human cunning, by craftiness in deceitful schemes. 15 Rather, speaking the truth in love, we are to grow up in every way into him who is the head, into Christ, 16 from whom the whole body, joined and held together by every joint with which it is equipped, when each part is working properly, makes the body grow so that it builds itself up in love.
This was more than just about numbers, it was more about quality than quantity.
I believe one of the reasons our evangelism is ineffective, is that first of all our discipling within the Body is ineffective, or maybe close to non-existent sometimes?
Remember that those who were directly given "The Great Commission" had been discipled by the Master Himself for a few years. And as we read of some of their interactions we can see that it was not an easy thing. And discipling is never easy.
And yet it must be done in order to send out effective evangelists.
The second way of evangelism that I had mentioned earlier for members of the Body who were not expressly given as evangelists can be perhaps best expressed by what Peter says;
1 Peter 3:13-17 English Standard Version (ESV)
13 Now who is there to harm you if you are zealous for what is good? 14 But even if you should suffer for righteousness' sake, you will be blessed. Have no fear of them, nor be troubled, 15 but in your hearts honor Christ the Lord as holy, always being prepared to make a defense to anyone who asks you for a reason for the hope that is in you; yet do it with gentleness and respect, 16 having a good conscience, so that, when you are slandered, those who revile your good behavior in Christ may be put to shame. 17 For it is better to suffer for doing good, if that should be God's will, than for doing evil.
Every believer's life is to be a possible instrument of evangelization, and every believer's word is to be available at any time as an instrument of evangelization.