[if] “salvation is the ultimate goal (which it is), Everything we need to know about salvation and our daily walk with Christ is in the Scriptures...
I reject the premise. Salvation has never been the ultimate goal or else ALL would be saved.
The ultimate goal is for God to reveal His Glory. (Ps 113:4-6)
The Lord is high above all nations,
His glory above the heavens.
Who is like the Lord our God,
Who dwells on high,
Who humbles Himself to behold
The things that are in the heavens and in the earth?
Given the last statement, we find that salvation is all but a small part of how God's manifests His glory. He delights in lifting up the poor and needy out of the dust and ash heaps and seating them among the princes. He turns the hearts of kings, forms and channels the rivers, defines the boundaries, calls His people to Himself. Therefore there is Glory in the works of Righteousness that come from our daily activities.
To limit the "Why" to just "salvation" is to be a Deist, not a friend of God.
AMEN
Psalm 113:1 Praise the LORD.[a]
Praise the LORD, you his servants;
praise the name of the LORD.
2 Let the name of the LORD be praised,
both now and forevermore.
3 From the rising of the sun to the place where it sets,
the name of the LORD is to be praised.
4 The LORD is exalted over all the nations,
his glory above the heavens.
5 Who is like the LORD our God,
the One who sits enthroned on high,
6 who stoops down to look
on the heavens and the earth?
7 He raises the poor from the dust
and lifts the needy from the ash heap;
8 he seats them with princes,
with the princes of his people.
9 He settles the childless woman in her home
as a happy mother of children.
Praise the LORD.
The context of the verse you lifted from Psalms 113 changes when you see the whole Psalm as written, especially verses 7-9. A great deal of God’s glory seems invested in the kindness God longs to show to mankind. The Psalmist is praising God in that God in all his glory longs to lift up fallen man to himself...
and to that I too lift up my voice!
{I PRAISE YOU OH GOD!}
It is certainly true that God “doesn’t need us” and is simply “glorious” for who HE IS! Yet when he put his thumbprint into our matter universe, coming in the flesh, sending his son Jesus only to be put to death for our sins, you can’t tell me that God hasn’t put forth a very significant investment of his own Glory for our sakes. Indeed, I think that makes God, all the more “GLORIOUS”!
{Again I PRAISE YOU, OH GOD...for allowing me the priviledge and my very existence to utter praises to YOU and of your NAME!}