The evidence of Things not seen
Heb 11:1 — Now faith is the substance of things hoped for, the evidence of things not seen.
In the spiritual realm, all promises of the One True Living God are apprehended by faith. Like all key words in the bible, faith is not something that is easily defined. The above verse from Hebrews is probably the best definition available. I’ve felt that faith often is a heart-knowledge of God. It is a reality that I’ve never seen God, yet slowly over a period of time, He has become more of a reality than any other human being or a material object. God can at best be explained by the apostolic introduction “come and see” — a response to the call of the most high.
Why would God make Himself so hard to see ? The fact is, He doesn’t. All heavens declare the glory of God (Psa 19). Even the people who are, as yet, unfamiliar with God have their consciences declare the person and nature of God (Rom 2:14–15). The entire volume of the bible is the word of God written to bring all of mankind into a relation with the creator God, and for the eternal salvation of he who would be lost but for the grace of God.
2 Cor 4:18 — While we look not at the things which are seen, but at the things which are not seen: for the things which are seen [are] temporal; but the things which are not seen [are] eternal.
Whatever we see today will be transformed and will not last for eternity. Yet, what we cannot see now — like God, angels, heaven, hell — these become the ultimate reality when the current heavens and earth shall pass away.
How naive, if we (who can spend eternity with God), forsake it because of utter disregard for the reality of eternity, and spend our whole lives laboring for that which perishes, and that which cannot save !