How has God demonstrated His love for you in your life? What are some examples (from the recent or distant past) where He has shown Himself faithful to you?
What are the theological implications of the reality that God is our Father? What are the theological implications of the reality that God is our Master?
Where in your life are you tempted to offer God something less than your best?
If you are married, how can you be working to honor your spouse more effectively? How can you be proactively demonstrating your love to him/her? If you are single, how can you be preparing yourself to do this more effectively in the future?
In 3:14-15, the Israelites complain that it is pointless to serve God, and they point to the prosperity of people that are arrogant and wicked. How can we, as Christians, work to trust God, and walk with Him, even when it goes unnoticed, or unrewarded? Or even when wickedness goes unpunished?
How does the book of Malachi function to set up the New Testament, and to prepare the reader for what is to come?