Gen 12:1-3
1Now the LORD had said to Abram: "Get out of your country, from your family and from your father's house, to a land that I will show you.
2 I will make you a great nation; I will bless you and make your name great; and you shall be a blessing.
3 I will bless those who bless you, and I will curse him who curses you; and in you all the families of the earth shall be blessed." NKJV
The life of Abraham is a living prove of God’s calling faithfulness to His calling over every man on earth, He called Abraham out of his country and from his kindred even from his father house and God gave him a commandment to go into a land that will show him. God promise Abraham to bless him
Gen 12:2-3
2 I will make you a great nation; I will bless you and make your name great; and you shall be a blessing.
3 I will bless those who bless you, and I will curse him who curses you; and in you all the families of the earth shall be blessed." NKJV
Genesis chapter 12:1-3 shows a pattern of every divine calling that is for every calling of God upon man there is always an unlimited promises of blessing attached to it and the almighty God is absolutely faithful to all his covenant and promises for man. Abraham was called out of his country to a prophetic office
Gen 20:6-7
6 And God said to him in a dream, "Yes, I know that you did this in the integrity of your heart. For I also withheld you from sinning against Me; therefore I did not let you touch her. 7 Now therefore, restore the man's wife; for he is a prophet, and he will pray for you and you shall live. But if you do not restore her, know that you shall surely die, you and all who are yours." NKJV
Abraham obeyed God and act on the inturction God gave him, Abraham’s obedience to that calling made God to be committed to the fulfilment of His promises for Abraham, don’t forget that Abraham was tested before he was trusted with the covenant and the promises of God. Many people always think of sustenance and what will become of them if they accept the calling of God, don’t forget that God is ever faithful to His calling what God expect you to do is to trust and obey him
Deut 5:29-30
29 Oh, that they had such a heart in them that they would fear Me and always keep all My commandments, that it might be well with them and with their children forever! NKJV
Don’t forget you will pass through trials but be of good cheer for it is finish on the cross what you have to do is to proceed don’t think on how God will do it, it’s too big for you to understand how he will do it, Just obey.

Source:http://www.kingdomflow.net.ng/christian-leadership/gods-faithfulness-to-his-call/