Isaiah 57:15 highlights topic of God's existence, His promise of peace from world.
For thus saith the high and lofty One that inhabiteth eternity, whose name is Holy; I dwell in the high and holy place, with him also that is of a contrite and humble spirit,to revive the spirit of the humble, and to revive the heart of the contrite ones.
God is above all and when He says High and Lofty these words are different to other times used in Bible or in common English it is God who is high-high above, so to say some one is high we as fallen man compare to things of His creation but God is high compared to everything, man was made from dust and even dust was created by God that is how he is top of creation.
He inhabiteth eternity that is His place of dwelling which is understood never-ending place and He is called Holy there is no one named Holy apart from God. So in human sense to define God we always seek for comparison and truth is we can't find any comparison in His own creation as all are His work and He is above all and it is hard to explain Him in this world but can only explain as HOLY.
He dosen't dwells among us as He is holy, and in Old Testament we see jews had alter to worship God which is clear picture of His uniqueness and just and Isaiah describes as He dwells in heaven. God is not alone He dwells with someone for fellowship and that is us.
If any Christian fellowship is not dwelleth with God then that fellowship is not Holy.
When God says contrite spirit it is crushed spirit which also refers to dust h1793. דַּכָּא ḏaḵâ’; from 1792; crushed (literally powder, or figuratively, contrite): — contrite, destruction. and thats where we came from, as we dust can have riches of this world but without Him we are no more than just dust. Till we deny our own sins God won't dwell in us, if we are pride of our self then still God won't dwell with us.
Fellowship refers to some thing in common
To be in fellowship with God we need to be Humble which reflects cross,
But he giveth more grace. Wherefore he saith, God resisteth the proud, but giveth grace unto the humble. James 4:6
Humility is not terminated with salvation but it mush continue in all our life in order to dwell with God.
Draw nigh to God, and he will draw nigh to you. Cleanse your hands, ye sinners; and purify your hearts, ye double minded. Be afflicted, and mourn, and weep: let your laughter be turned to mourning, and your joy to heaviness. Humble yourselves in the sight of the Lord, and he shall lift you up. James 4:8-10
Fellowship needs suffering as one who loved God is not conformed to this world or one who belongs to it in fact he is transformed out of the world to be like Him.
Requirements for Christians to comply with God's fellowship is by imitating Him that is focusing and working to become like Him which is known as sanctification. God never said to worship Him for a while in church, prayer or bible study and do evil at rest of time, in fact He asks us to be Holy all the part of our life. So fellowship with God is,
- thinking what He does
- think what He likes
As it is personal application to produce Spiritual fruits But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith, Meekness, temperance: against such there is no law. Gal 5:22-23. If I bear fruit of flesh, Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness, Idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies, Envyings, murders, drunkenness, revellings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God. Gal 5:19-21 then I am friend of this world. Our purpose which God has set is to create hunger of truth to others. We are not following people who resists God but following who fellowship with God. Seek for those who are humble before God's presence not there own.
Prime creator for fellowship is humble and he lives in Holy place with humble one and not pride, rich, great, self talkers, etc, but with Humbles Thus saith the Lord, The heaven is my throne, and the earth is my footstool: where is the house that ye build unto me? and where is the place of my rest? For all those things hath mine hand made, and all those things have been, saith the Lord: but to this man will I look, even to him that is poor and of a contrite spirit, and trembleth at my word. Isaiah 66:1-2, For fellowship we look for one who bow knees to God.