Jesus is indeed the Good Shepherd willing to go all out to deliver and save His sheep from destruction. It is also true that He laid His life for the salvation and redemption of the lost sheep (John 10:11).
But even though the sheep cannot save itself unless by the shepherd's help, it has a role to play for His salvation to become a reality. It must take a step, which is to return to Jesus (1 Peter 2:25).
To return is to acknowledge that you're truly missing, lost, and cannot find your way back home (Romans 3:23). It means to accept that only Jesus, the Great Shepherd, can save you from your sins and restore you to God (Psalm 23:3).
If you want to return to Jesus, you must confess your sins to be saved and washed with the blood of Jesus and accept Christ as your Savior (1 John 1:9, Romans 10:9).
Why must you be washed with the blood? In as much as Jesus is willing to take you back into the fold, He is too holy to associate with sin (Isaiah 59:1, Habakkuk 1:13). Therefore, He will need to sanctify you so that you can be presentable to God and then accepted (Hebrews 10:10).
When you take these steps, Jesus becomes the Guardian of your soul. He will keep your soul secured. He will nourish and empower it with His Spirit. Your soul will find rest under His guardians.