… to prepare God's people for works of service, so that the body of Christ may be built up until we all reach unity in the faith and in the knowledge of the Son of God and become mature, attaining to the whole measure of the fullness of Christ (Eph 4:12-13).

There are two things that the church needs to seek in order that it may be built up: it is to reach “unity in the faith,” and to reach unity “in the knowledge of the Son of God.” The latter is easy to understand concerning why it is necessary: it is because the church is the body of Christ, and without the true knowledge of the Son of God, it cannot function as such. Then, what about the unity in faith: why does the church need to seek it?

First of all, we need to keep in mind that the building-up of the body of Christ is creation, and it demands faith on our part in order for that creation to be realized. And regarding how faith works for creation, we see a good example in the life of Abraham: he was old and his wife Sarah was a barren woman. From a physical point of view, it was impossible for them to have a baby, but not so in faith. Faith creates things and gives life to the dead.

As it is written: "I have made you a father of many nations." He is our father in the sight of God, in whom he believed--the God who gives life to the dead and calls things that are not as though they were. Against all hope, Abraham in hope believed and so became the father of many nations, just as it had been said to him, "So shall your offspring be (Rom 4:17-18)."

Just as God created this world by calling light when there was no light, we, by faith, call things that are not as though they were. Abraham, by faith, called himself “a father of many nations” when there was no hope in his sight.

Without weakening in his faith, he faced the fact that his body was as good as dead--since he was about a hundred years old--and that Sarah's womb was also dead. Yet he did not waver through unbelief regarding the promise of God, but was strengthened in his faith and gave glory to God, being fully persuaded that God had power to do what he had promised. This is why "it was credited to him as righteousness (vv. 19-22)."

In chapter 15 of Genesis, we read that Abraham grumbled about his situation—no children to inherit his estate. God said to him:

Do not be afraid, Abram.

I am your shield, your very great reward (Gen 15:1)."

It was right after Abraham and his 318 men went out to fight against the kings who had come to conquer Sodom and Gomorrah. He brought back Lot and his family, together with the citizens of the cities. He saved others, but had no children of his own. So, God told him to count stars in the sky, and when he did, he chose to accept the reality that God offered—“So shall your offspring be”—instead of the reality which he had been grumbling about.

Abram believed the Lord, and he credited it to him as righteousness (v. 6).

This was the beginning of the creation that Abraham experienced afterwards. It was not only the beginning of the creation of his life, but also the beginning of the creation of God’s people, and eventually of the creation of the whole humanity, because out of Abraham came the nation of Israel, and out of Israel came the messiah, Jesus Christ. It all started with one person who came to have faith as small as a mustard seed. Where there is no faith, there is no creation. It is by this faith that the body of Christ may be built up. The church needs to learn more about faith, and seek to reach “unity in the faith.”

From the fruit of his mouth a man's stomach is filled;

with the harvest from his lips he is satisfied.

The tongue has the power of life and death,

and those who love it will eat its fruit (Prov 18:20-21).

The first step of learning about faith is to learn the importance of our mouth confessions. Your tongue is very powerful, and it works for both “life and death”