"A congregation is indeed gathered out of the nations, but it is obligated by God to send forth the gospel message to the nations."
-J.H. Bavinck, An Introduction to the Science of Missions
As a campus minister, I yearn to see students, faculty, and staff come to faith in the Lord Jesus Christ. I desire to see them discover the wonders of God's grace, generally, in the world--from blooming flowers and athletic prowess to exquisite artwork and the intricacies of engineering--and, particularly, in the redemptive work of Christ--His life, death, resurrection and ascension. I want them to know that the Kingdom of God has broken into this world, and, as a result, they are witnesses and ambassadors of its King, the Lord Jesus Christ, in their given vocations; in all that they say and do--wherever God leads them.
This is, by no means, a unique desire. In fact, it is one shared by many ministries on the university campus. While we may approach the kerygmatic task in different ways, we all desire to see the gospel go forth, and disciples made. And beyond the campus, this should be the heart of those who make up our churches. If a passion for proclaiming the gospel--the good news concerning Christ and the Kingdom--in both word and deed is lacking in the local church, serious questions must be asked. As J.H. Bavinck points out in his classic book, An Introduction to the Science of Missions, as a people graciously gathered out of the world by the Triune God, we are obligated to take this message forth to the nations.
And while churches may do this differently, and (campus) ministries use various approaches, there are certain rules that Bavinck identifies that transcend all these differences; rules that we should take heed of today, all these years later, as we continue to walk in obedience to the calling given us by our God and King.
1. We must try to see the person with whom we are dealing.
Bavinck's first point is that we cannot simply get caught up with the surface details of the person with whom we are dealing; their name, position, and arguments. We need to remember that the person before us is not simply a man or woman (a family member, foreigner, neighbor, co-worker, friend, etc.), but is also a worshipping being and a bearer of culture, which is to say, their life is religiously oriented (it is just a matter of what it is oriented around). Beneath the surface are a complex network of fears, desires, hopes, dreams, worries, and, as Augustine so famously stated, a restlessness that only finds its rest in a right relationship with God. With this in mind, Bavinck reminds us: "Behind all such arguments and deliberations there lies hidden a personal meeting with God. "
2. The approach must be a meeting filled with love.
Oftentimes, we are guilty of approaching people as projects; simply identifying others as the lost, blind, and/or foolish. As a result, our engagement with people regarding the good news of the Christ can be far from caring and compassionate, filled with loving patience and grace. I can recount numerous stories from non-Christians who, having not converted in a short period of time, watched their Christian "friends" disappear (presumably to find the sheep God was calling back to the fold). Bavinck explains:
Not until I see all things such as stupidity, primitiveness, and deceit as the elements constituting the structures of their flight from God and responsibility, can I begin to have room for love. For then I realize that apart from God's grace, this same flight from God is also the deepest motive of my own life. I try to flee in an infinitely more subtle manner, but I nevertheless flee, until Christ draws me out of my darkness and opens my eyes. 
Bavinck's words are oriented toward native peoples in foreign lands, but the same principle can be applied to our own context. We must remind ourselves that this person is a fellow image-bearer of God--one made in His image--and recognize, via our common guilt before God and equal need for His grace, ourselves in those with whom we engage. Meetings and relationships covered in love, care, and compassion are a crucial supplement to words we speak. Again, Bavinck writes:
Our meeting with others must be marked by a certain calm and patience, if we are to understand a person's manner of life, his basic presuppositions, and his secret defenses. In many instances we will have to take a person seriously, even though we sometimes have a mind to strike him abruptly with the sword of God's Word...Our own desire ought never to hinder our proceeding with caution and concern. 
3. It must bear the character of an encounter.
This is defined by Bavinck as "[Moments that take place] if two people permit the light of God's word to shine over their life." It is a moment of two people standing together before God. To put it another way, this rule pertains to the moment in which a person is ready and willing to hear, and we are faithful and prepared, to share the Word of God concerning Christ and His Kingdom. Such moments can arise in corporate settings, such as a church service or campus meeting, but most often occur in the intimate setting of a one-on-one conversation. And they can occur when we least expect them. I would argue this, of the three rules, is the trickiest to identify, and, at times, can even take place without our knowing it, as God works in and through us, the meeting, or the growing relationship.
So take these three rules to heart as you engage in the task given us by our Lord Jesus Christ to make known the good news. See the person with whom you are meeting; fill that meeting with love; and submit yourself, the relationship, and your discussion, before the Lord God according to His Word. And may He bless us with an abundance of fruit, joy, and thanksgiving.
 Bavinck, drawing on Kraemer, broadly identifies two approaches: the spontaneous and the cautious. The spontaneous would encompass what many campus ministries and church evangelistic programs do, in directly calling people to "give themselves to Christ." The cautious, on the other hand, is a longer, prolonged effort of addressing an individual's questions, defenses, and arguments, culminating with the final step: a call to repentance and faith.
 Bavinck, J.H., Introduction to the Science of Missions (Philadelphia, PA: P&R Publishing Co., 1960), 122.
 Bavinck, 126.
 Bavinck, 127.
 Bavinck, 128.