See what the writer of Hebrews wrote in Hebrews 6:4-6: "It is
impossible for those who have once been enlightened, who have tasted the
heavenly gift, who have shared in the Holy Spirit, 5 who have tasted the goodness of the word of God
and the powers of the coming age, 6 if they fall away, to be brought back to repentance, because to
their loss they are crucifying the Son of God all over again and subjecting him
to public disgrace." The point is being made that those who have had their eyes opened, received the Holy Spirit and experienced the goodness of God's word and they fall away--what could possibly prompt them to return to God? Their departure suggests all the goodness of God weighed in their scales was not as sweet as sin and serving self, and in their pride God is lesser and expendable. Of course what is impossible with man is possible with God, and His will is for all to be saved--even people who have departed from faith in Him. But the point remains valid, that when some people are inoculated against God and the Gospel it is impossible to change their hardened hearts and minds.
Notice what the apostate does by departing from faith in Jesus Christ: they crucify the Son of God all over again. In falling away from Jesus, they are as the people who shouted "Crucify Him!" out of envy whose loyalties lay elsewhere. Such did not lament His death and felt it was beneficial He was gone. The second part of verse 6 also shows another consequence of apostacy, that Jesus is subjected to public disgrace. Honouring Jesus publicly is of great importance for the Christian, and something we ought to desire to do ourselves. God asked through the prophet in the first half of Malachi 1:6: "A son
honours his father, and a servant his
master. If then I am the Father, where is My honour? And if I
am a Master, where is My
reverence?..." We call God our heavenly Father, and we ought to honour Him (at the very least!) at the level of our earthly father. Since God is our LORD and the LORD of Hosts, He is worthy of all reverence and obedience. We ought to be more zealous in giving Jesus honour than being concerned what people stand to lose by departing from Him.
The author of Hebrews finished the paragraph with an illustration in Hebrews 6:7-8: "Land
that drinks in the rain often falling on it and that produces a crop useful to
those for whom it is farmed receives the blessing of God. 8 But land that produces thorns and thistles is
worthless and is in danger of being cursed. In the end it will be burned." Two fields are contrasted here that align with one who remains faithful to God and one who departs from Him: one drinks in the rain and produces a fruitful crop, and the other produces thorns and thistles and is worthless. The one who is faithful to abide in Christ and receive the Living Water will be blessed, and the one marked with thorny consequences of sin is in danger of being cursed. When a field was overgrown with thorns and thistles, a farmer would use fire to clear it. By being a fruitful field we bring honour to our Father and Master, and we are blessed for it. Those who find this blessed arrangement unacceptable will face the consequences. It is required in servants to be faithful, and may we be those who publicly honour Christ.