Taking the Staff of God
In Exodus 3:7-8 God makes a clear statement of His intent to rescue Israel - in fact He says it is as good as done: 'I have come down to rescue ...' or more accurately 'I am come down'. And when God says something we can know for certain that it is a done deal! Moses no doubt is relieved to hear this, but when the Lord says: 'So go. I am sending you', Moses isn't so sure. But when God acts, it is usually through human agency that He chooses to work - in this instance it is Moses!
And having called Moses, God also equips him - we see how God puts into Moses hand, power and authority. Indeed in 4:20 we read that Moses returned to Egypt taking the Staff of God in his hand.