We must pay the most careful attention, therefore, to what we have heard, so that we do not drift away.
In the letter to the Hebrews, the writer warns us I believe, that true, genuine believers can lose their salvation. Not because they didn’t have it in the first place, although some fit into that category, as well. (See Hebrews 10 and especially Hebrews 6). Regardless of where we stand on this debate (and although I stand on one side, I’m a bit of an agnostic on matters like this), we can agree that there are strong warnings. And that we don’t want to drift away from the faith and suffer shipwreck, in other words have our faith destroyed. This certainly does happen.
This doesn’t mean that we need to get into a defensive mode and posture at all. It does mean that we need to be those who are of faith in the faith. We need to be committed to go on, come what may. And not unlike the pressures the Christians faced to leave the faith who were addressed in the letter to the Hebrews, we face pressures as well from our society.
Certain interpretations of scripture may not impact the faith, although they may indicate a faulty hermeneutic that arguably may well undermine it. The gospel must be intact: Jesus in his incarnation, works and teaching concerning the kingdom of God, his death and resurrection, his ascension, and the promise of his return. That must all remain intact. Usually currents which may push us out into waters in which we are too deep and far removed from shore (Lake Michigan has this phenomena, a kind of undertow on certain days which ends up drowning a number of people) begin in more subtle ways. Scripture addresses them, so that we need to be in the written word daily so that we can be alert and remain faithful in and through God’s grace in Jesus.
For me I think I begin losing out when everything seems to be okay. Not without struggles and issues, but when I seem to be at rest concerning them. Instead of drifting off into some kind of solitude and silence (although that has its place in faith), I need to give thanks and press on. My life has been so full of trials, that if it seems like the trials are either gone, or not that big of a deal (more the latter for me now), I can lack in sense of needing God. But the Lord wants us to go on, to follow him no matter what, through good times and bad, no matter what we feel or are experiencing.
Half the battle is knowing of this danger. The other half is learning how to go on and finish well, inspite of it. Reading the entire letter to the Hebrews is not a bad place to start.