Maturation is an on-going process.
Philippians 3:12-13
2 Peter 1:5-10

Our speech and actions reveal the level of our maturity.
Proverbs 9:6
Proverbs 15:2
Proverbs 29:11
Ecclesiastes 10:12-13
James 3:2

We become mature when we learn to take responsibility for ourselves and others.
Lamentations 3:27
Romans 14:12
Galatians 6:2
Philippians 2:12

Steppingstones to maturity:
Proverbs 20:11
Proverbs 23:24-25
1 Corinthians 13:11
Ephesians 4:14
Titus 2:4b,6
2 Timothy 2:22
1 John 2:13b-14

Spiritual maturity depends on our connection with the Lord and His Word.
Psalm 16:8
Daniel 11:32b
Matthew 13:3-8,18-23
John 15:4-5
1 Timothy 4:15-16
2 Timothy 3:15-17