As a dog returns to its vomit, so a fool repeats his foolishness.

Don't give what is holy to dogs or toss your pearls before pigs, or they will trample them with their feet, turn, and tear you to pieces.

Watch out for "dogs," watch out for evil workers, watch out for those who mutilate the flesh.

It has happened to them according to the true proverb: A dog returns to its own vomit, and, “a sow, after washing itself, wallows in the mud.”
-Prov. 26:11, Matt. 7:6, Phil. 3:2, 2 Pet. 2:22

We had a couple of dreams about dogs.  In the first dream, a full grown dog was unfriendly towards me.  It was threatening and intimidating.  In the second dream, I brought home a full grown lion and a little dog.  The small dog did not like the big lion.

In ancient times, dogs were simile's for unclean, scavenger, lowlifes.  It was a negative label to give someone.  Dogs symbolize unbelief or unbelievers who are not walking in God's way.  They represent people who are unregenerate, which is defined as: 
1.  Not renewed or reformed in heart and mind or reborn in spirit; unrepentant and incorrigible.
2.  Not reconciled to change; unreconstructed, cantankerous.
3.  Stubborn; Persistently unwilling to accept change: recalcitrant, bullheaded, pertinacious, intractable, or obstinate.

Dogs signify people who are unregenerate.  The dog way or the dog life-style is the refusal of discipleship and the pressing forward in life, without Christ at the center or core, as the dynamism.

What is sobering, and should give us pause, is that these lessons about dogs, given in each verse above, are given to and within the community of faith.  There is always the potential for those who believe, or seemed to have believed, to choose not to believe.  And, belief, according to Jesus, is shown by how you live: what you do.  It is not enough to know it, but we must put it in to practice in our living.

In Philippians 3:2, Paul says, Observe" or "Take a lesson from", "Those dogs".  The lesson to learn might be, that we all can become just like the very religious, yet unregenerate, people who preached, taught, evangelized, and acted as missionaries for their brand of religion, that was, to put it bluntly, wrong.  We need to observe the error of, "Holding to the form of godliness but denying its power" (2 Tim. 3:5).    We might believe in Messiah, but give Him no power over our lives.

The warning of the dog returning to it's vomit in foolishness, is taken up by Peter in 2 Peter 2:22, as a pastoral critique (to put it mildly) against unregenerate false teachers.  One thing that is shocking is that Peter says that these unregenerate people once knew the way of righteousness, but turned back from it (2 Pet. 2:21).

Choices are made to not walk with Christ and yield to his life in ours.  Christ wants to touch us, but we may choose to be out of touch.  2 Peter, chapter 2 is a warning, that it can happen to any of us.  We can make selfish choices and become unregenerate.

The NT is full of warnings to carefulness, watchfulness, and being on guard.  We have to watch out that we don't deceive our selves.  The simple antidote to deception is to stay close to the truth, have an intimate relationship with Him.  Tell Him everything and ask Him all your questions.  It is impossible to bear fruit, be regenerated, when you are not in the vine

Beware of the unregenerate people, the unregenerate pathway, or the unregenerate lifestyle that is not in Christ.  Observe the "dog's life" and know that it is the choice people make, who choose not the Lion's life.  The dogs are opposed to the lion and to His life in us.  Choose Christ's life.

The picture above is from chapter 3 of Charles Spurgeon's Autobiography, wherein he wrote:
I once learnt a lesson, while thus fox-hunting, which has been very useful to me as a preacher of the gospel. Ever since the day I was sent to shop with a basket, and purchased a pound of tea, a quarter-of-a-pound of mustard, and three "pounds of rice, and on my way home saw a pack of hounds, and felt it necessary to follow them over hedge and ditch (as I always did when I was a boy), and found, when I reached home, that all the goods were amalgamated,-tea, mustard, and rice,-into one awful mess, I have understood the necessity of packing up my subjects in good stout parcels, bound round with the thread of my discourse; and this makes me keep to firstly, secondly, and thirdly, however unfashionable that method may now be. People will not drink mustardy tea, nor will they enjoy muddled-up sermons, in which they cannot tell head from tail, because they have neither, but are like Mr. Bright's Skye terrier, whose head and tail were both alike.