Four questions need to be answered: 

Does the Bible teach that drinking wine is wrong? 
Am I toasting something God would approve?  
Do I fall into bad behavior when I drink wine?  
How does my behavior affect others?

The Bible urges us to be cautious with drinking wine. The scriptures teach that getting drunk (the excess) causes problems and is the sin.  “Do not get drunk on wine, wherein is excess.  Instead, be filled with the spirit” (Ephesians 5:18).  “Do not join those who drink too much wine or gorge themselves on meat, for drunkards and gluttons become poor, and drowsiness clothes them in rags” (Proverbs 23:20-21).

Drinking wine itself cannot be a sin because our Lord Jesus created wine at the wedding of Cana (John 2:1-11). Also, the Apostle Paul told Timothy, “Stop drinking only water, and use a little wine because of your stomach and your frequent illnesses” (1 Timothy 5:23). These verses illustrate that consuming wine is acceptable. 

May a conscientious Christian participate in a toast with an alcoholic drink? Joining a toast indicates approval of the function and of the good wishes of that toast. Therefore, one needs to ask if Jesus would attend that event?

Additionally, are the words/wishes of the toast honorable? If your answers are yes, then you may participate in the well-wishes!

A problem arises if drinking alcoholic beverages troubles your conscience. If that is the case, you should not do it. “I always do my best to have a clear conscience before God and people” (Acts 24:16 ISV).  Romans 14:21 says it is good to not drink wine if it could stumble someone. This means that if we are around someone who thinks it is wrong to drink wine or who has a weakness for drinking, it may be wiser to abstain. 

Jesus taught us to “love your neighbor as yourself” (Matthew 22:39, Mark 12:31). It is good to consider how our behavior affects others. The best rule is to remember, “So whether you eat or drink or whatever you do, do it all for the glory of God” (1 Corinthians 10:31).

Additional Resource:
Christian Questions Podcast
Episode #1200: “Could an Addiction Block My Christian Growth?”
Learning to identify and manage compulsive and addictive behavior
Preview Video
CQ Rewind Show Notes

Episode #1351: “What Defines Moral Behavior? (Part II) God-Driven Direction”
Properly managing our varied Christian perspectives of right and wrong
Preview Video
CQ Rewind Show Notes