Many times as I talk with Christian brothers and sisters, they express the same fear.  They tell me that they know how weak they are and that they are afraid that they might backslide and fall away altogether.   I have struggled with the same fear and I too, have heard the voice of the enemy, trying to convince me that I am not right with God.  I battle doubt too, from time to time.  We have to make up our minds that doubt and fear will not be the final authority over us, but that we will submit everything to the Word of God.
The Word says in Jude 1:24
Now all glory to God, who is able to keep you from falling away and will bring you with great joy into his glorious presence without a single fault.
And in  John 6: 35 – 40
35 Then Jesus declared, “I am the bread of life. Whoever comes to me will never go hungry, and whoever believes in me will never be thirsty. 36 But as I told you, you have seen me and still you do not believe. 37 All those the Father gives me will come to me, and whoever comes to me I will never drive away. 38 For I have come down from heaven not to do my will but to do the will of him who sent me. 39 And this is the will of him who sent Me, that I shall lose none of all those he has given me, but raise them up at the last day.40 For my Father’s will is that everyone who looks to the Son and believes in him shall have eternal life, and I will raise them up at the last day.”
Psalm 23:3, 4  He restores my soul; He leads me in the paths of righteousness For His name’s sake.
Even though I walk through the darkest valley, I will fear no evil, for you are with me; your rod and your staff, they comfort me.   NIV
When we are weak, when we transgress, when we are confronted with the condition of our hearts – even things that are so bad that it could lead us to spiritual death, Jesus is more than able to preserve us.  The Father’s will is still (as it’s been from the beginning of time) that none should be lost.  How much more is that true for us, adopted into his family by the sacrifice of Jesus.
When we go through the “valley of the shadow of (spiritual) death”  – those times when we have to deal with hidden sin, the attitudes of our heart, where we begin to understand how far we stray from the Lord’s will and purpose for our lives, we can rest assured that He will guide us with His staff and that he will discipline us with His rod of correction – to preserve us so he is able to present us blameless, without a single fault.
Every Christian will pass through this valley, the place where we begin to be complacent, the place where we lose concentration, those times when we get tired or just plain lazy. It is in these times when we become vulnerable to the enemy, where the shadow of spiritual death begins to hover closer.  It is in these times, the times when we doubt our salvation, where we are exasperated, frustrated, upset, ill, in pain, whatever it is that happens,  that the enemy convinces us that Jesus is not enough. When all of a sudden we begin to doubt the work done on the cross, our standing with the Lord, our ability to hear His voice, the lack of spiritual fruit in our lives and our inability to move in the gifts of Holy Spirit, we have to refocus.  We have to fix our eyes on Jesus again and we have to choose to believe every promise given to us in the Word of God.
We have to remind ourselves of the scriptures I quoted, and many other like these.  We cannot trust in our emotions, we cannot trust in our ability to interpret what we see in the physical world around us, we cannot trust the voices of even Christian brothers, sisters and leaders.  We can only allow ourselves to trust in the Word and promises of the Lord.  Before Jesus died, He said “It is finished”.  It is indeed finished.  The work was done at the cross.  All we need to do is to stay buried in Jesus and trust Him to present us to the Father, washed in His own blood.  Father, Son and Holy Spirit is the same yesterday, today and forever.  They do not move, they do not change – we do.
So let us make up our minds that we will submit ourselves to the Lord’s rod and staff, that we will allow Him to teach and train, discipline and guide us through the scriptures and through the Holy Spirit.  Let us be quick to repent and turn back to Him and let us follow closely behind Him as He leads us in the way everlasting.