Is the act of prayer spiritual?
As the Bible teaches us, prayer offers Christians the opportunity to speak directly to God in the name of Jesus Christ with the help of the Holy Spirit as they enter into communion with the Lord. This is a spiritual act of worship glorifying God and a privilege offered to Christians. On the other hand, merely assuming a posture of prayer and "going through the motions" is not - by itself - a spiritual act.
Prayer is a spiritual process and goes beyond just words, and the Holy Spirit plays an essential role in our prayer life. It is an act of worship from the heart according to the will of God, and it depends upon the Holy Spirit directlng our thoughts and guiding our words, whether spoken or thought. As Paul taught:
Rom. 8:26 In the same way the Spirit also helps our weakness; for we do not know how to pray as we should, but the Spirit Himself intercedes for us with groanings too deep for words;
Rom. 8:27 and He who searches the hearts knows what the mind of the Spirit is, because He intercedes for the saints according to the will of God.
Furthermore, our prayer is spiritually meaningful and effective because we have a relationship with Christ, Who serves as our High Priest to intercede on our behalf, which is why we pray in the name of Jesus Christ.
Heb. 4:14 Therefore, since we have a great high priest who has passed through the heavens, Jesus the Son of God, let us hold fast our confession.
Heb. 4:15 For we do not have a high priest who cannot sympathize with our weaknesses, but One who has been tempted in all things as we are, yet without sin.
Heb. 4:16 Therefore let us draw near with confidence to the throne of grace, so that we may receive mercy and find grace to help in time of need.
So prayer is the unique privilege of God's people, and it is a spiritual act for us. For those who lack a personal relationship with the Father through His Son, prayer is not spiritual; it is merely posing. The Bible says that the Father only hears the prayers of His children, and He does not incline His ear to the prayers of an unrighteous (i.e., unbelieving) man.