Romans 11:20 They were broken off because of their unbelief, but you stand fast through faith. So do not become proud, but fear. For if God did not spare the natural branches, neither will he spare you. Note then the kindness and the severity of God: severity toward those who have fallen, but God’s kindness to you, provided you continue in his kindness.
James 2:19 You believe that God is one; you do well. Even the demons believe—and shudder!
Hebrews 3:12 Take care, brothers, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God.
Revelation 3:17 For you say, I am rich, I have prospered, and I need nothing, not realizing that you are wretched, pitiable, poor, blind, and naked.
Hebrews 3:19 So we see that they were unable to enter because of unbelief.
Hebrews 4:6 Since therefore it remains for some to enter it, and those who formerly received the good news failed to enter because of disobedience,
Hebrews 4:11 Let us therefore strive to enter that rest, so that no one may fall by the same sort of disobedience.
Isaiah 66:2 All these things my hand has made, and so all these things came to be, declares the LORD. But this is the one to whom I will look: he who is humble and contrite in spirit and trembles at my word.
Hebrews 4:1 Therefore, while the promise of entering his rest still stands, let us fear lest any of you should seem to have failed to reach it.
Paul said, “note the severity and kindness of God”. We have a natural thought that clings to God’s kindness but sidelines and thoughts to His severity of judgment, wrath, and anger. We cling to “For God so loved the world that He gave His only begotten Son” but we give little thought of His wrath and anger against unbelief, trust, faith, and obedience in/on Jesus Christ. Paul saw how easy it was for believers to fall into disobedience. He saw how they became complacent and neglectful of things of God. They became lukewarm towards seeking and desiring to honor and glorify Him. Over and over again Paul urged people to remain steadfast and to not forget the grace, mercy, kindness, and love of God. Paul had to be dismayed when he would return to towns he had once been and had seen great numbers of people believe in Jesus Christ, only to find they had become neglectful and complacent in their devotion to God. Paul so how easy it was for the heart of man to fall away from being fully committed and living for God every moment of every day. God’s kindness and severity remain true and steadfast. We do well to our hearts, minds, soul, and our daily lives in line with the Word of God at all times lest we become disobedient through neglect and complacency.