Busy Men Called

Nehemiah while serving his king as cupbearer:

Nehemiah 1:11 

O Lord, I beseech thee, let now thine ear be attentive to the prayer of thy servant, and to the prayer of thy servants, who desire to fear thy name: and prosper, I pray thee, thy servant this day, and grant him mercy in the sight of this man. For I was the king's cupbearer.

Nehemiah 2:10 

When Sanballat the Horonite, and Tobiah the servant, the Ammonite, heard of it, it grieved them exceedingly that there was come a man to seek the welfare of the children of Israel.

Peter and Andrew from fishing:

Matthew 4:18-20 

18 And Jesus, walking by the sea of Galilee, saw two brethren, Simon called Peter, and Andrew his brother, casting a net into the sea: for they were fishers.

19 And he saith unto them, Follow me, and I will make you fishers of men.

20 And they straightway left their nets, and followed him.

Matthew from the tax office:

Matthew 9:9 

And as Jesus passed forth from thence, he saw a man, named Matthew, sitting at the receipt of custom: and he saith unto him, Follow me. And he arose, and followed him.

Please read the following passages for other references.