It is important to attend church for the following reasons:
(1) It is an Expression of our Love for God
Going to church is a visible, tangible expression of our love and worship toward God. It is where we can gather with other believers to publicly bear witness of our faith and trust in God, something that is required of all Christians (Matt. 10:32-33) -- and it is where we can bring Him offerings of praise, thanks, and honor, which are pleasing to Him. The psalmist wrote, "I will declare Your name to My brethren; In the midst of the assembly I will praise You" (Psa. 22:22). People are often motivated toward church attendance for how it will bless themselves, however we should remember that the primary purpose of the corporate gathering is to bring "service" to the Lord as a blessing to Him (Psa. 134:2). Indeed, the Lord is deserving of our time and energy to honor Him with our service of devotion. "You are worthy, O Lord, To receive glory and honor and power; For You created all things, And by Your will they exist and were created" (Rev. 4:11).
(2) It builds up our Spiritual Strength
Receiving the preaching and teaching of the Word of God increases our faith and builds us up spiritually. Every believer knows what it is to face spiritual conflicts to their faith, and must realize the importance of being fed spiritually so that they can overcome the challenges. Paul states that Christians face a wrestling match with the Devil and his evil spiritual forces, and warns that the church must put on spiritual armor for protection, as it will take everything at our disposal to stand (Eph. 6:10-18). How important that we take every opportunity available to receive ministry and strength from God's Word. "So then faith comes by hearing, and hearing by the word of God" (Rom. 10:17).
(3) It brings a special visitation of the Lord's Presence
There is the promise of a special visitation of the Lord's presence whenever two or more gather specifically in the name of Jesus. By implication, this means whenever "Jesus" is the object of gathered prayer, worship, praise, preaching, etc. Even though Jesus resides within the heart of every believer, he honors a gathering in his name by coming in the "midst," with his power, awareness, and anointing. In such a gathering, Christ is able to do things in hearts that he may not at any other time. The scripture says that God inhabits the praise of His people (Psa. 22:3), and in such an atmosphere the Holy Spirit will often manifest spiritual gifts that minister to the body of Christ. "For where two or three are gathered together in My name, I am there in the midst of them" (Matt. 18:20).
(4) It provides fellowship with other Christians
Gathering together also has compounded importance to the relationship of the Christian brethren. The Bible makes it clear that a right relationship with God requires a "vertical" and "horizontal" alignment -- that is, we must have a vertical fellowship with God and a horizontal fellowship with other believers. It is not possible to love God and refuse to love the brethren. If you have a problem loving other Christians, you have a problem in your relationship with God. Scripture warns us that unforgiveness toward others will void God's forgiveness of our own sins (Matt. 6:15). John wrote, "He who says he is in the light, and hates his brother, is in darkness until now. He who loves his brother abides in the light, and there is no cause for stumbling in him" (1 John 2:9-10).
One of the most important reasons that we go to church is to practice love toward the brethren in the form of fellowship. The Bible clearly shows that if we have a right relationship with God, we have fellowship with others believers. "But if we walk in the light as He is in the light, we have fellowship with one another, and the blood of Jesus Christ His Son cleanses us from all sin" (1 John 1:7). Keeping ourselves in love and harmony with other believers keeps us humble before God so that Christ's blood can continue to cleanse us from our sins.
(5) It is an act of obedience to God
Not to be forgotten, going to church is also a matter of obeying God's Word. The writer of the Hebrew epistle tells us not to forsake assembling together, implying that continued absence can lead to willful sin. "And let us consider one another in order to stir up love and good works, not forsaking the assembling of ourselves together, as is the manner of some, but exhorting one another, and so much the more as you see the Day approaching. For if we sin willfully after we have received the knowledge of the truth, there no longer remains a sacrifice for sins," (Heb. 10:24-26). Once again, we are reminded that a great part of the purpose of the gathering is for the consideration of our brethren, coming together to help motivate and encourage one another. This is a responsibility charged to every believer. To reject church attendance, is a rejection of one of the sacred duties of the believer. "Therefore, to him who knows to do good and does not do it, to him it is sin" (James 4:17).
(6) It provides accountability to spiritual leadership
More strong evidence that proves that we're to be a part of a church fellowship, is that we're told to submit to the authority of spiritual leaders (within the boundaries of God's Word). "Obey those who rule over you, and be submissive, for they watch out for your souls, as those who must give account. Let them do so with joy and not with grief, for that would be unprofitable for you" (Heb. 13:17). God designed this system of accountability for the progress and protection of His flock. Obviously, this really isn't possible unless we are a part of an organized fellowship which has identified elders, pastors, or leaders. It is easy to see that one cannot genuinely be under submission to a TV pastor who has never met you. Nor is it possible to be under submission by visiting a different church each week. The Bible tells us to know them that are over us in the Lord (1 Thes. 5:12). Submission necessitates a commitment and relationship to a local body of believers and to their spiritual leaders.
(7) It combines our spiritual strength in prayer
The Bible indicates that agreement in prayer with other believers has special favor with God. "Again I say to you that if two of you agree on earth concerning anything that they ask, it will be done for them by My Father in heaven" (Matt. 18:19). There is multiplied strength in the combined faith of God's people, and it is clear that greater spiritual gains can be realized through corporate prayer and worship. This agrees with how God has historically blessed the union of His people in battle against their enemies. "Five of you shall chase a hundred, and a hundred of you shall put ten thousand to flight; your enemies shall fall by the sword before you" (Lev. 26:8).
(8) It honors the Lord's Day
The fourth commandment of the law that God gave Moses was to set aside the seventh day of the week, Saturday, as a holy day to the Lord. "Remember the Sabbath day, to keep it holy" (Ex. 20:8). This was, and will always remain, the official Sabbath. However, after Jesus rose from the dead on the first day of the week, Sunday, the early Christians began meeting together on this day as well as with the Jewish community in the synagogues on the Sabbath. History indicates that due to the enmity of the orthodox Jews toward the Christian Jews in their midst, the Jewish Christians were eventually ostracized. And although they were no longer bound to a rigid code of laws (Gal. 3:10-11, Col. 2:16), it is believed that they came to view Sunday as a combined observance of the Sabbath and the resurrection day of Jesus (Acts 20:7, 1 Cor. 16:2). This day of Christian worship came to be called the Lord's Day (Rev. 1:10), a day to fellowship in celebration of the resurrection, to worship, pray and study the Word together.
Today, the Christian Jew or gentile, is free from the bondage of the old law. The indwelling of God's spirit has brought a new way for Christians to fulfill the desires of God through His love (Gal. 5:18, Rom. 13:8-10). However, the new covenant does not invalidate the relevance of the ten commandments as they pertained to God's wishes for His people. As much as it remains God's desire for man not to kill, steal or commit adultery, God is still very much pleased for believers to honor Him on a day reserved for Him, out of their love for Him and His people.