Psalm 34:22

The LORD redeems his servants;
no one who takes refuge in him will be condemned.
Psalm 34:22, TNIV

Here we see that the key thing for salvation is where we take refuge; what we hold onto as our only hope when everything else is gone. We also see by the parallelism that God's servants are those who take refuge in him - that taking refuge in God is inseparable from serving him, and serving him properly understood is inseparable from taking refuge in him.