There's a tendency in life to allow things to settle; to grow tired of maintaining one's health, one's relationships; to stop putting in the effort. It's not too surprising, then, when we lapse into a sort of walking coma in our spiritual lives.
Salvation, in its most basic form, is belief in the Lord Jesus Christ. If the basis of salvation is simply belief, we can hold onto it without a shred of effort. Simply choose a belief, and neglect to challenge it, and you can maintain it indefinitely without another thought.
But salvation is also based on a relationship with God. Because of this, effort must be put into it, in order for it to thrive and grow. To be saved means to put one's life in submission to your Savior, allowing Him to change you and use you as He sees fit. If we don't actively look to engage in that relationship, it will become stale and lose its power.
2 Timothy 1:6&7
Therefore I remind you to stir up the gift of God
which is in you through the laying on of my hands.
7 For God has not given us a spirit of fear, but of power
and of love and of a sound mind.
God's spirit in us, is there on purpose; to empower us, love us and ease our troubled minds. He wants us to stir up the gift He's given us. Use it! Engage with Him, activate the gift He's given you.
John 15:4
Abide in me, and I in you. As the branch cannot bear fruit by itself,
unless it abides in the vine, neither can you, unless you abide in me.
God sent His Spirit to commune with us; to connect with us on a personal and intimate level. Engaging in that relationship through prayer, meditation on scripture, worship, allows the Spirit to speak to us, direct us and bear fruit in our lives.
Revelation 3:20
Behold, I stand at the door and knock.
If anyone hears my voice and opens the door,
I will come in to him and eat with him, and he with me.
It's God's job to do the saving. It's our job to respond to His initiating Spirit. He comes to us, looking for communion, looking for connection and fellowship. The decision is ours, whether we will put in the effort, open the door, and stir up the gift within us.
One day at a time, moment by moment He leads, He speaks. Help us hone our listening hearts, Father.