I don't see any suggestion as to salvation in Matthew 7:26-27
It just plainly states that those that do NOT ACT on the teachings of Jesus will experience a fall.
How are they self-explanatory?
Paul is saying that nothing can separate you from God.
Jesus is saying that something can separate you from God.
Which is it?
There are several vital principles in biblical hermeneutics, one of them it to ascertain what the subject is, from the context. The subject in Romans 8:38,39 is the saved; the subject in Matt. 7:26-27 is the unsaved.
Matt. 7:21-27 (A.V.)
21 ¶
Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven.
22
Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works?
23 And
then will I profess unto them, I never knew you: depart from me, ye that work iniquity.
24 ¶ Therefore whosoever heareth these sayings of mine, and doeth them, I will liken him unto a wise man, which built his house upon a rock:
25 And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell not: for it was founded upon a rock.
26 And
every one that heareth these sayings of mine, and doeth them not, shall be likened unto a foolish man, which built his house upon the sand:
27 And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell: and great was the fall of it.
Jesus says that this is eternal life, to know thee, the only true God, and Jesus Christ whom thou hast sent; but, in Matt. 7:23, he makes it crystal clear that he
never knew these fake Christians, which means that they were never saved. This contrast between the saved and unsaved continues in the following verses.
A house that falls has been destroyed. This should really be obvious.
Rom. 8:28-39
28 And we know that all things work together for good to them that love God, to them who are the called according to his purpose.
29 For
whom he did foreknow, he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brethren.
30 Moreover whom he did predestinate, them he also called: and whom he called, them he also justified: and whom he justified, them he also glorified.
31 What shall we then say to these things? If God be for us, who can be against us?
32 He that spared not his own Son, but delivered him up for us all, how shall he not with him also freely give us all things?
33 Who shall lay any thing to the charge of God’s elect? It is God that justifieth.
34 Who is he that condemneth? It is Christ that died, yea rather, that is risen again, who is even at the right hand of God, who also maketh intercession for us.
35
Who shall separate us from the love of Christ? shall tribulation, or distress, or persecution, or famine, or nakedness, or peril, or sword?
36 As it is written, For thy sake we are killed all the day long; we are accounted as sheep for the slaughter.
37 Nay, in all these things we are more than conquerors through him that loved us.
38 For I am persuaded, that neither death, nor life, nor angels, nor principalities, nor powers, nor things present, nor things to come,
39 Nor height, nor depth, nor any other creature, shall be able to separate us from the love of God, which is in Christ Jesus our Lord.
This passage is about God's elect, chosen from before the foundation of the world. These people are foreknown (i.e. God has set his familial knowledge upon them beforehand, choosing them); they are predestined (their destiny has been decided in advance); they are called, justified and, finally, glorified. This is called "the golden chain" - an unbroken chain that ensures the salvation of those whom God has chosen to save. The promises in verses 38 and 39 are based on the fact that salvation is of the Lord, not of man's will or works, so nothing can separate us from the love of God, in Christ Jesus our Lord.