Milk, meat, and fruit trees

When someone first becomes a believer, they have little understanding of how to follow Messiah Yeshua and what is expected of them.  They first understand the 'milk' of the gospel: that Messiah Yeshua was born of a virgin, was fully God and fully man, lived a sinless life, died on the cross to atone for sins of the world,  bodily resurrected three days later, and bodily ascended to heaven.  They do not understand what Yahweh's  rules for living are and understand the need to live a holy life through the power of the Holy Spirit.

When a believe gains maturity, they are expected to live a more holy life and be able to discern between what is true and what is false. 

Hebrews 5
5  So neither did the Messiah glorify himself to become cohen gadol; rather, it was the One who said to him, "You are my Son; today I have become your Father."
6  Also, as he says in another place, "You are a cohen forever, to be compared with Malki-Tzedek."
7  During Yeshua's life on earth, he offered up prayers and petitions, crying aloud and shedding tears, to the One who had the power to deliver him from death; and he was heard because of his godliness.
8  Even though he was the Son, he learned obedience through his sufferings.
9  And after he had been brought to the goal, he became the source of eternal deliverance to all who obey him,
10  since he had been proclaimed by God as a cohen gadol to be compared with Malki-Tzedek.
11  We have much to say about this subject, but it is hard to explain, because you have become sluggish in understanding.
12  For although by this time you ought to be teachers, you need someone to teach you the very first principles of God's Word all over again! You need milk, not solid food!
13  Anyone who has to drink milk is still a baby, without experience in applying the Word about righteousness.
14  But solid food is for the mature, for those whose faculties have been trained by continuous exercise to distinguish good from evil.

1 Corinthians 3
1  As for me, brothers, I couldn't talk to you as spiritual people but as worldly people, as babies, so far as experience with the Messiah is concerned.
2  I gave you milk, not solid food, because you were not yet ready for it. But you aren't ready for it now either!
3  For you are still worldly! Isn't it obvious from all the jealousy and quarrelling among you that you are worldly and living by merely human standards?

When one is a mature believer, they are expected to know what is Yahweh's truth and what is deception.  They are also expected to expel the evildoers from their fellowships - not entertain their false teachings.  They are also expected to know the difference between a true believer and a false believer.

1 Corinthians 5
9  I wrote unto you in an epistle not to company with fornicators:
10  Yet not altogether with the fornicators of this world, or with the covetous, or extortioners, or with idolaters; for then must ye needs go out of the world.
11  But now I have written unto you not to keep company, if any man that is called a brother be a fornicator, or covetous, or an idolater, or a railer, or a drunkard, or an extortioner; with such an one no not to eat.
12  For what have I to do to judge them also that are without? do not ye judge them that are within?
13  But them that are without God judgeth. Therefore put away from among yourselves that wicked person.

The old testament shows the maturity expected of a believer by the law of the fruit trees.  When a fruit tree is young, they are not expected to bear fruit.  As they are maturing, their fruit is to glorify Yahweh as they start living holier by the power of the Holy Spirit,  Once they are fully mature, they can bare fruit for Yahweh and go out and teach the scriptures and bear fruit by whatever the Holy Spirit leads them to do.

Leviticus 19
23  And when ye shall come into the land, and shall have planted all manner of trees for food, then ye shall count the fruit thereof as uncircumcised: three years shall it be as uncircumcised unto you: it shall not be eaten of.
24  But in the fourth year all the fruit thereof shall be holy to praise the LORD withal.
25  And in the fifth year shall ye eat of the fruit thereof, that it may yield unto you the increase thereof: I am the LORD your God.

Yeshua expected a fig tree to bear fruit at a certain time and when it didn't, He cursed it so it would not bare fruit ever again:

Matthew 21:19  And when he saw a fig tree in the way, he came to it, and found nothing thereon, but leaves only, and said unto it, Let no fruit grow on thee henceforward for ever. And presently the fig tree withered away.

Yeshua also gave a parable that the tree was expected to bear fruit for Yahweh after the third year:

Luke 13
6  He spake also this parable; A certain man had a fig tree planted in his vineyard; and he came and sought fruit thereon, and found none.
7  Then said he unto the dresser of his vineyard, Behold, these three years I come seeking fruit on this fig tree, and find none: cut it down; why cumbereth it the ground?
8  And he answering said unto him, Lord, let it alone this year also, till I shall dig about it, and dung it:
9  And if it bear fruit, well: and if not, then after that thou shalt cut it down.

Scripture is clear that a believer is to grow in maturity and bare fruit as he matures in the faith.  As a believer matures, they are expected to lead a holier life and to bear fruit otherwise they are in a danger of being cut down.  Messiah also states a good tree IS to bear good fruit otherwise the tree will be cut down and thrown into the fire along with the bad trees.

Matthew 7
16  Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles?
17  Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit.
18  A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit.
19  Every tree that bringeth not forth good fruit is hewn down, and cast into the fire.
20  Wherefore by their fruits ye shall know them.

To bear good fruit, you MUST obey Yahweh - doing things for Yahweh is not considered good fruit UNLESS you are OBEYING what Yahweh says to do - IE: follow Torah:

Matthew 7
21  Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Fatherwhich is in heaven.
22  Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and inthy name done many wonderful works?
23  And then will I profess unto them, I never knew you: depart from me, ye that work iniquity.^G458

Strong's number G458 iniquity (transliterated as anomia)   :
anomia
1) the condition of without law
     a) because ignorant of it
     b) because of violating it
2) contempt and violation of law, iniquity, wickedness

John 14:15  If ye love me, keep my commandments.

John 14:23  Jesus answered and said unto him, If a man love me, he will keep my words: and my Father will love him, and we willcome unto him, and make our abode with him.

John 15:10  If ye keep my commandments, ye shall abide in my love; even as I have kept my Father's commandments, and abide in his love.

1 John 2
3  And hereby we do know that we know him, if we keep his commandments.
4  He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.

1 John 5
2  By this we know that we love the children of God, when we love God, and keep his commandments.
3  For this is the love of God, that we keep his commandments: and his commandments are not grievous.

Revelation 14:12  Here is the patience of the saints: here are they that keep the commandments of God, and the faith of Jesus.
.