spiritual maturity

Therefore let us leave the elementary teachings about Christ and go on to maturity, not laying again the foundation of repentance from acts that lead to death, and of faith in God, instruction about baptisms, the laying on of hands, the resurrection of the dead, and eternal judgment. And God permitting, we will do so. (Hebrews 6:1-3)

The word in Greek for maturity or perfection here is ‘teleiotes.’ It comes from the Greek word ‘telos’ which means to make perfect, to carry through completely, to accomplish, finish, bring to an end, to accomplish.

It is used in the context of doing the will of God
"Epaphras, who is one of you and a servant of Christ Jesus, sends greetings. He is always wrestling in prayer for you, that you may stand firm in all the will of God, mature and fully assured." Col. 4:12

It is used in the context of being able to distinguish good from evil.
But solid food is for the mature, who by constant use have trained themselves to distinguish good from evil. Heb. 5:14

It is used to mean sacrifice
"Jesus answered, ‘If you want to be perfect, go, sell your possessions and give to the poor, and you will have treasure in heaven. Then come, follow me.’" Matt. 19:21

It is used to mean love.
"You have heard that it was said, ‘Love your neighbor and hate your enemy.’ But I tell you: Love your enemies and pray for those who persecute you, that you may be sons of your Father in heaven. He causes his sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous. If you love those who love you, what reward will you get? Are not even the tax collectors doing that? And if you greet only your brothers, what are you doing more than others? Do not even pagans do that? Be perfect, therefore, as your heavenly Father is perfect." Matthew 5:43-48

Perhaps this last one is the most important.

Sacrifice, obedience to God, distinguishing good from evil, all are perfected in love. All are only possible in love.

Jesus told us what the first and greatest commandment is. He said, "‘Love the Lord your God with all your heart and with all your soul and with all your mind.’ And the second is like it: ‘Love your neighbor as yourself.’" (Matt. 22:37-39).

Jesus also said, "A new command I give you: Love one another. As I have loved you, so you must love one another. By this all men will know that you are my disciples, if you love one another" (John 13:34-35).

This is the level of maturity that God wants from you: A perfect faith. The only way to perfect your relationship with God and improve your walk in holiness is do it by faith and obedience to His word.

God does not command where He does not provide or empower.

God works faith in the believer (John 6:29).

God has given everyone a measure of faith (Rom. 12:3).

"But prove yourselves doers of the word, and not merely hearers who delude themselves," (James 1:22).

You can mature and grow in the grace and knowledge of the Lord Jesus.

Love is patient,
love is kind.
It does not envy,
it does not boast,
it is not proud.
It is not rude,
it is not self-seeking,
it is not easily angered,
it keeps no record of wrongs.
Love does not delight in evil
but rejoices with the truth.
It always protects,
always trusts,
always hopes,
always perseveres.
Love never fails.
1 Corinthians 13:4-7