The People Principle: God uses people to be channels of His provision for His work.
Ezra 1:3-4 Who is there among you of all his people? his God be with him, and let him go up to Jerusalem, which is in Judah, and build the house of the Lord God of Israel, (he is the God,) which is in Jerusalem. 4 And whosoever remaineth in any place where he sojourneth, let the men of his place help him with silver, and with gold, and with goods, and with beasts, beside the freewill offering for the house of God that is in Jerusalem.
In Ezra 1:3-4, God was looking for people to go and people to help. The first question after they are commanded to rebuild the temple is “Who?” God could have chosen to use angels, animals, or anything else, but He chose to use people. All through the Bible, we find God using people.
When God told Moses to build a tabernacle, he provided everything and more than they needed for the tabernacle through the people (Exodus 36:6).
When God told Solomon to build the temple, he had already provided much of what he would need through the diligent preparation of David.
When God told the disciples go to out, he told them that God would provide for their support through others (Acts 10:5-10).
Paul taught that a man does not go to warfare at his own expense and neither should a preacher be expected to pay his own way, though he should be willing to work if necessary and never be greedy of money (1 Corinthians 9:6-11).
God enabled Paul to do all things and he was content, but the church at Philippi did well in how they were used by God to help him (Philippians 4:10-20).
Yes, God could do miracles or anything He wants to get His work done, but He used people. God wants to use you to get the gospel to the lost. You may not go, but you can used by God to send someone.