On Perseverance of the Saints, to which neither DHK, nor BobRyan, nor those of their ilk understand, I will explain the position.
Their argument is that we say we need to do something to remain saved. That's untrue.
They argue we don't know if we are saved. That is also untrue.
When we talk about perseverance of saints it is their actual preservation by Christ in eternal salvation and by His securing His sheep -- John 10:26ff.
I didn't name the 'P' in TULIP, and I admit it is poorly worded, yet you two take off with the surface statement and run with it like you have the true meaning and then create your straw man ideologies and beat upon them. Frankly you don't have and never have had the true meaning of this position. Php. 1:6, John 10:28, Eph. 1:13ff, Hebrews 12:2 &c show it is all Christ, and these passages reflect OSAS and perseverance of saints which is really preservation.
That said show me one Calvinist/Reformed on here who has said we need to do something to remain saved. You can't, because it hasn't happened, so what you do instead is put words in their mouths and refuse to acknowledge that they in fact have it exactly correct. On top of that I can show you some on here who are not of our camp that do in fact say this, and use passages of what others must do to 'get to heaven'. That is a clear cut denial of Solus Christus.
Another thing about perseverance that we adhere to is that we will continue in the faith until the end, because of Christ's abiding power in us, and because we are truly regenerate (2 John 1:2).
We also understand that those who depart, go out from among us, were never truly saved, Matthew 7:22ff and 1 John 2:19 (these were NEVER known by Christ/They were NEVER of the saints, were not ever saved) and this is true no matter what their profession was in the past.
So in a nutshell those who are TRULY regenerate will never lose salvation, and those who were not truly regenerate as described above never lose salvation because they never had it in the first place, no matter what they've professed in the past. This is why the Holy Spirit gave these passages so it would be evident they were never saved in the place.