What is the Gap Theory? Did anything happen between Genesis 1:1 and 1:2?

Romans 16:17  Now I beseech you, brethren, mark them which cause divisions and offences contrary to the doctrine which ye have learned; and avoid them.
Rom 16:18  For they that are such serve not our Lord Jesus Christ, but their own belly; and by good words and fair speeches deceive the hearts of the simple.

I was just reading John Gill's(an 18th century theologian) commentary on this - he makes some interesting points - one of them being not only false teachers(and ungodly men who crept in unawares) bringing in damnable heresies, but they also cause alot of divisions and strife among the body of Christ. We saw this last year when Greg Miller pushed this gap theory heresy - he ended up sowing seeds of strife among the body of Christ(it came to a point where everyone was just literally mudslinging each other on YT comments section, that it just nearly damaged our testimony to the lost world, and made us look foolish in front of those very perverted version readers that we expose).

I never understood that clearly what "divisions and offences" really is(other than false doctrine) - I think this clears it up a bit more...

http://www.biblestudytools.com/commentaries/gills-exposition-of-the-bible/romans-16-17.html

Romans 16:17

Now I beseech you, brethren
The apostle being about to finish his epistle, and recollecting that he had not given this church any instructions about the false TEACHERS, who had been the cause of all their differences and uneasiness, inserts them here; or he purposely put them in this place, amidst his salutations, that they might be taken the more notice of; and very pertinently, since nothing could more express his great affection and tender concern for them; and these instructions he delivers to them, not in an authoritative way, as he might, and sometimes did, but by way of entreaty, beseeching them, and with the kind and loving appellation of brethren, the more to engage them to attend to what he was about to say to them:

mark them which cause divisions and offences, contrary to the
doctrine which ye have learned.
The men he would have taken notice of were such who divided them in their religious sentiments, introducing heterodox notions, contrary to the doctrine of the Scriptures, of Christ and his apostles, and which they had learned from them; such as justification by the works of the law, the observance of Jewish days, and abstinence from meats, enjoined by the ceremonial law, and that as necessary to salvation; to which some gave heed, and others not, and so were divided; whereas the doctrine of faith is but one, the Gospel is one uniform thing, all of a piece; and those that profess it ought to be perfectly joined together in the same mind, and in the same judgment: hence their minds were alienated from each other, and they began to despise and judge one another, yea, to go into factions and parties, being unwilling to receive and admit each other to communion; and thus by these men they were divided in sentiments, affection, and worship; and which must needs cause offence to the church and the godly members of it, as well as cause many so to be offended, as to stumble and fall from the doctrine of faith, and profession of it, and greatly stagger and distress weak believers, and bring a scandal on religion, and the name and ways of Christ among the world, as nothing does more so than the jars and discords among Christians: wherefore the apostle advises to "mark" such persons, look out for, narrowly watch, strictly observe, and diligently examine them: the metaphor is taken from watchmen, who look out from their watch tower, and observe who are coming, or pass by, and take up suspicious persons, and carefully inquire who they are, and what they are about, and whether friends or foes. So both ministers of the Gospel, and members of churches, should not be asleep, which is the opportunity false teachers take to sow the seeds of false doctrine, discord, and contention, but should watch, and be upon their guard, and look diligently, that none among them fail of, or fall from, the doctrine of grace, or any root of bitterness, error, or heresy as well as immorality, spring up, which may be troublesome, and defile others; they should observe, and take notice of such who are busy to spread false doctrine, should watch their motions, follow them closely, take them to an account, examine their principles ACCORDING to the word of God; and if found to be contrary thereunto, note them as false teachers:

and avoid them;
shun their ministry, drop attendance on it, depart far from them, have no private conversation with them, receive them not into their houses, nor bid them God speed; with such do not eat, have no communion with them at the Lord's table, WITHDRAW from them as disorderly persons, who act contrary to the doctrine and order of the Gospel, and after proper admonition reject them from all fellowship with you.