One may object to halal meat for a variety of reasons (e.g., the methods of slaughter that are employed, the serving of such meats to school children who don't get a choice as to what their school serves for lunch, the Islamization of the meat industry, etc.). However, the question about Christians eating halal meat is usually based on a passage in 1 Corinthians 10. Muslims pronounce Islamic phrases (bismillah, "in the name of Allah," and Allahu akbar, "Allah is greater") over animals as they are slaughtered, so many Christians wonder if eating the meat of these animals is condemned by the Apostle Paul. Here's the first part of the relevant passage:
1 Corinthians 10:14-22—Therefore, my beloved, flee from idolatry. I speak as to wise men; you judge what I say. Is not the cup of blessing which we bless a sharing in the blood of Christ? Is not the bread which we break a sharing in the body of Christ? Since there is one bread, we who are many are one body; for we all partake of the one bread. Look at the nation Israel; are not those who eat the sacrifices sharers in the altar? What do I mean then? That a thing sacrificed to idols is anything, or that an idol is anything? No, but I say that the things which the Gentiles sacrifice, they sacrifice to demons and not to God; and I do not want you to become sharers in demons. You cannot drink the cup of the Lord and the cup of demons; you cannot partake of the table of the Lord and the table of demons. Or do we provoke the Lord to jealousy? We are not stronger than He, are we?Notice that Paul is specifically discussing meals that function as part of worship. He refers to the "Lord's Supper," in which Christians gather for a meal commemorating the sacrificial death of Jesus. He also mentions Jewish sacrifices, in which the person who brings the offering consumes a portion of the sacrifice (as do the priests).
1 Corinthians 10:23-31—All things are lawful, but not all things are profitable. All things are lawful, but not all things edify. Let no one seek his own good, but that of his neighbor. Eat anything that is sold in the meat market without asking questions for conscience’ sake; for the earth is the Lord’s, and all it contains. If one of the unbelievers invites you and you want to go, eat anything that is set before you without asking questions for conscience’ sake. But if anyone says to you, “This is meat sacrificed to idols,” do not eat it, for the sake of the one who informed you, and for conscience’ sake; I mean not your own conscience, but the other man’s; for why is my freedom judged by another’s conscience? If I partake with thankfulness, why am I slandered concerning that for which I give thanks? Whether, then, you eat or drink or whatever you do, do all to the glory of God.Since Paul advises Christians to "eat anything that is sold in the meat market without asking questions for conscience' sake," he obviously doesn't care whether the animal has been slaughtered in the name of a false deity. He even says that it's perfectly acceptable to join a pagan for a meal, knowing that the meat may have been slaughtered as a sacrifice to a pagan deity.
Paul's concern is when the meal is eaten as part of worship, and the impact this may have on new or weak Christians who have been raised to think of the idols as objects of worship. Indeed, Paul's remark about the "table of demons" is connected to chapter 8, where he refers to "dining in an idol's temple" (1 Corinthians 8:10). Such meals were part of the worship of idols, and if new or weak Christians see Christians eating in the temples of idols, they may be tempted to join in the worship of the idols.
Applying these principles to the question of halal meat, an important difference becomes apparent. Although Islamic phrases are recited over the animals when they are slaughtered, this isn't the sort of sacrificial worship Paul discusses in 1 Corinthians. "Halal" simply means "allowed" or "permissible," not "sacred." Halal meat has met basic requirements for being consumed by Muslims. This doesn't mean it was prepared as part of Islamic worship.
But even if we view halal meat as somehow sacrificed to Allah, this shouldn't be a concern, because the god of the Qur'an, like the idols of Corinth, is nothing. Hence, Christians should have no religious objection to eating halal meat, whether in a store, at a restaurant, or at the home of a Muslim friend. The only exception would be if we are in the presence of Christians who are sincerely bothered by the eating of halal meat, because they think of it as somehow honoring Allah. In such cases, Paul says that we shouldn't eat the meat (1 Corinthians 8:13).
Again, there may be other concerns about halal meat. One may object to the treatment of the animals or to the application of Sharia principles in Western industries. But if we are wondering whether Paul says that we are sinning by eating halal meat, we can see that his only warnings for us are: (1) Don't eat halal meat as part of any worship towards Allah, and (2) Don't eat halal meat if a new or weak Christian is bothered by it. Apart from those cases, the general rule is that "everything created by God is good, and nothing is to be rejected if it is received with gratitude; for it is sanctified by means of the word of God and prayer" (1 Timothy 4:4-5).
For more on this topic, here's John Piper: