"Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God." Hebrews 3:12
Can you be lost after once tasting the goodness of eternal life? You certainly can! The above scripture is enough to show anyone that, even though they have once prayed and asked Christ into their heart, they can be cast away because of unbelief. Notice it says "in departing from the living God." You can't depart from something you first aren't a part of. So what causes someone to be lost?
"But exhort one another daily, while it is called To day; lest any of you be hardened through the deceitfulness of sin." Hebrews 3:13
The answer is in the verse above – sin! We are told to exhort, beseech, or entreat each other not to fall back into sin and to watch out for the traps that Satan may be trying to lay for us. We are in a battle and, even though our Lord Jesus Christ has paid the price, we are still warring against the devil and the flesh.
"Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour:" 1 Peter 5:8
"For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would." Galatians 5:17
From the above two verses we plainly see that we are fighting the devil and our flesh. Unfortunately most in the church do not realize that this is a warfare and not just something for us to "feel good" or "make us rich." Of course, in this free and easy, self-centered culture that we live in today that is not popular, but true. However, we do have a promise.
"For we are made partakers of Christ, if we hold the beginning of our confidence stedfast unto the end;" Hebrews 3:14
We can continue fellowship with him if we hold our confidence and faith in him.
If we keep from falling into a sinful state of unbelief and our love wax cold. "And because iniquity shall abound, the love of many shall wax cold." Matthew 24:12
If we keep in fellowship with him, each other, and walk in the light we can continue in the faith. "But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin." 1 John 1:7
If we bear fruit and abide in him we will not be cut off but our prayers can be answered. 2 Every branch in me that beareth not fruit he taketh away: and every branch that beareth fruit, he purgeth it, that it may bring forth more fruit. 3 Now ye are clean through the word which I have spoken unto you. 4 Abide in me, and I in you. As the branch cannot bear fruit of itself, except it abide in the vine; no more can ye, except ye abide in me. 16 Ye have not chosen me, but I have chosen you, and ordained you, that ye should go and bring forth fruit, and that your fruit should remain: that whatsoever ye shall ask of the Father in my name, he may give it you." John 15:2-4,16
It is essential that we keep fellowship with Christ by daily prayer and study. While Satan will do everything to take this from you, you must fight him and your flesh to maintain a life that is close to the Master. Yes, there are times when the heavens seem like brass and the earth as iron but if you and I continue to hold on to the truth and fight the good fight of faith, not only for ourselves but for others, we will be victorious in Him. Remember this one thing, that Christ can help you through any temptation if you let him as he is the faithful high priest.
"Wherefore in all things it behoved him to be made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people. For in that he himself hath suffered being tempted, he is able to succour them that are tempted." Hebrews 2:17-18