Moderation is perhaps the governing concept for a Christian view of bodybuilding/weightlifting. First Timothy 4:8 teaches,

for while bodily training is of some value, godliness is of value in every way, as it holds promise for the present life and also for the life to come. 1 Timothy 4:8 (ESV)

Physical fitness is important, and as this verse states, it has value. Unlike Plato contended, we are physical and spiritual beings joined together. The goal of life is not for the soul to escape the body. The condition of the physical body can undeniably impact our spirits. Surely part of “glorifying God in your body” (1 Corinthians 6:20) is keeping it in reasonably good physical condition. Bodybuilding can definitely be a part of a Christian’s physical fitness program.building, if taken to the extreme, can become an idol. A point is reached when there is no value in adding more muscle. In fact, too much muscle is unhealthy for your heart. Many muscle building supplements can pollute your body and destroy your liver. Bodybuilding/weightlifting can become an addiction and/or obsession. While this is more common with men, it can also be an issue for women. Striving for bigger and stronger muscles to have the perfect body, if taken to the extreme, is nothing but vanity.

But the Lord said to Samuel, “Do not look on his appearance or on the height of his stature, because I have rejected him. For the Lord sees not as man sees: man looks on the outward appearance, but the Lord looks on the heart.” 1 Samuel 16:7 (ESV)

but let your adorning be the hidden person of the heart with the imperishable beauty of a gentle and quiet spirit, which in God’s sight is very precious. 1 Peter 3:4 (ESV)

Once we allow our physical appearance to become more important than our relationship with God, it becomes an idol (1 John 5:21).

“So, whether you eat or drink, or whatever you do, do all to the glory of God” (1 Corinthians 10:31). The key question is does bodybuilding/weightlifting glorify God? If it is done to increase fitness, strength, and tone, and thereby health, yes, it can be done for God’s glory.

If it is done out of vanity and pride, or from an unhealthy obsession with getting bigger and stronger, no, it does not glorify God. How should a Christian view bodybuilding? “ ‘Everything is permissible for me’—but not everything is beneficial. “ ‘Everything is permissible for me’—but I will not be mastered by anything.… ‘Everything is permissible’—but not everything is constructive” (1 Corinthians 6:12; 10:23).