Marijuana is not mentioned in the Bible. However, smoking cannabis is considered intoxicating, just as wine is intoxicating. Therefore, the scriptural cautions about drinking wine would also apply to using marijuana. “Do not join those who drink too much wine or gorge themselves on meat,” Proverbs 23:20. “Do not get drunk on wine, which leads to debauchery. Instead be filled with the Spirit,” Ephesians 5:18.
Why is intoxication unhealthy? Because it can mask the sad consequences of life. When life brings us grief and pain, these problems should draw us to God and to the Bible. Marijuana provides a temporary escape from problems but never solves them. "Wine is a mocker…and whoever is led astray by it is not wise," Proverbs 20:1. Instead, we should seek help and wisdom from God. "If any of you lacks wisdom, you should ask God, who gives generously to all without finding fault, and it will be given to you," James 1:5 (NIV). It is by turning to God that we get to know Him and learn to love His ways.
Is wine evil? No. At the wedding at Cana (John 2:1-11), Jesus created between 108-162 gallons of wine. The Apostle Paul tells Timothy, “Stop drinking only water, and use a little wine because of your stomach and your frequent illnesses.” (1 Timothy 5:23) Therefore, drinking wine or (perhaps) smoking cannabis in moderation, occasionally, is permissible.
Cannabis can be used as medicine. It is used to relieve pain, improve the well being of chemotherapy patients, help prevent some cancers from metastasizing, and, perhaps, slow the progress of Alzheimer’s, to name just a few. Medicinal marijuana is prescribed by a doctor and is used under a doctor's supervision. Therefore, if a doctor prescribes marijuana, there should be no problem – providing the doctor monitors the patient. Marijuana is addictive, and Christians should be cautious. Sometimes an alternative, non-addictive treatment might be advisable.
Finally, whatever we do, we should do to the glory of God. The Apostle Paul teaches, "Therefore, whether you eat or drink, or whatever you do, do all to the glory of God. Give no offense, either to the Jews or to the Greeks or to the church of God, just as I also please all men in all things, not seeking my own profit, but the profit of many, that they may be saved," 1 Corinthians 10:31-33. If a person feels he cannot use marijuana to glorify God, or if he is stumbling others, then he should reconsider his actions.