"The same came for a witness, to bear witness of the Light, that all men through him might believe." (John 1:6 KJV)
"Then they that feared the LORD spake often one to another: and the LORD hearkened, and heard it, and a book of remembrance was written before him for they that feared the LORD, and that thought upon his name." (Malachi 3:16 KJV)
As far as I can tell, this witness is more than just a chance to reach those that are lost, because, as it turns out, God has full knowledge of those who will be His children; as it is said: 'God cannot learn, because He knows all things already!' But, God is full of love and mercy, therefore He offers redemption to each and every person, whether they want it or not, He gives everyone an chance to say yes or no.
The Light does not need any introduction, as the Light is a Witness unto Himself; but, because Light shines into the darkness, and the darkness cannot comprehend it, nor does it even want to, we have the witness of John the Baptist: who points the way to the Light, preparing the heart for a chance to receive what the Light has to offer.
The one who knows he is a sinner and sees his need for redemption, will most likely run towards the Light and want to be healed. Those that do not think they are sinners, will feel offended by the Light, because the sin they do not confess is exposed, therefore they will not accept what the Light has to offer and will remain in their sins.
No man or woman knows his or her chances to be in or out of redemption; but every single person knows whether or not they are actually saved! If you do not know for sure that you are saved, and you want salvation, then today is the day to make it happen! You never know what tomorrow will bring, but right now is the best opportunity to say, YES!, to God's free offer of Salvation! Just ask Him right now: Confess that you are a sinner and believe that Jesus Christ has paid the price for your sins; that He rose again to give you New Life; and now walk in that Life!
As for the Scripture from Malachi 3:16, it is just a reminder of what we can look forward to and why it is really important that we share what we know as often as we possibly can. Share with your spouse, your children, your friends; any and every chance you can get, to be ready in season and out of season to give a witness to the Light, that everyone you might meet will have a chance! God has given us a ministry, whether you might know it or not, it is to share our personal experience with the Light!
If you don't think that is your reasonable service, I think you need to think again; the Holy Spirit that is living within you wants to be poured out! Living Water must flow; if there is no flow, well, let's just say that there is no real power created to generate Life...
"And they shall be mine, saith the LORD of hosts, in that day when I make up my jewels; and I will spare them, as a man spareth his own son that serveth him. Then shall ye return and discern between the righteous and the wicked, between him that serveth God and him that serveth him not." (Malachi 3:17-18 KJV)