Wayne Grudem writes:

Becoming a Christian is a gift from God that requires our involvement; we find the same to be true for sanctification. Progress in sanctification is a gift of grace; but it is a gift we can expect to receive. Just as God honours our initial faith (faith that he gives us), he also honours our continual acts of faith and obedience …

It is important that we continue to grow both in our passive trust in God to sanctify us and in our active striving for holiness and greater obedience in our lives. If we neglect active striving to obey God, we become passive, lazy Christians. If we neglect the passive role of trusting God and yielding to him, we become proud and overly confident in ourselves. In either case, our sanctification will be deficient. And if our sanctification is deficient, we won’t experience the joy and peace promised to us (Galatians 5:22; Romans 14:17).

FROM: Wayne Grudem (ed. Elliot Grudem), Christian Beliefs: 20 Basics Every Christian Should Know (Inter-Varsity Press, Nottingham, England, 2005, (reprinted 2006).