If God knows the outcomes of our prayers, why does He call us to pray?

from the old testament

• God is sovereign, “declaring the end from the beginning” (Isaiah 46:10a). This means that everything that happens is because God declares it will happen. Within His sovereignty, God uses “means” to accomplish His will, one of which is prayer. For example, though God promised it would rain (1 Kings 18:1), He did so through Elijah’s prayer (1 Kings 18:42–45).
• We also pray to declare our reliance on God. God said, “and call upon me in the day of trouble; I will deliver you, and you shall glorify me” (Psalm 50:15). Another Psalmist wrote, “I lift up my eyes to the hills. From where does my help come? My help comes from the LORD, who made heaven and earth” (Psalm 121:1–2). These and other passages show that we pray because we depend on God.
• We also pray to express our relationship with God. David said, “O God, you are my God; earnestly I seek you; my soul thirsts for you; my flesh faints for you, as in a dry and weary land where there is no water” (Psalm 63:1). God because a relationship with God was everything to David.
• Prayer is part of our spiritual formation. In prayer, we confess our sins (Psalm 51) and ask God to examine us to show us our faults to which we are blind (Psalm 139:23–24). Prayer is also a way for us to align ourselves to God’s revealed will (i.e., Daniel 9).

from the new testament

• Prayer is one means God has ordained for Him to meet our needs. Jesus said, “Ask, and it will be given to you" (Matthew 7:7; cf. John 16:24), and James told his readers, “You do not have, because you do not ask” (James 4:2c). This doesn't mean we get whatever we ask for (thank God!); our motives matter to God (cf. James 4:3), and His will is still sovereign (Ephesians 1:11). But asking has a real effect on God satisfying our needs.
• Prayer also teaches us dependence on God. When Jesus taught His disciples how to pray, He said, “Give us this day our daily bread” (Matthew 6:11). Even our most basic needs come from God. Praying for them and later thanking Him for providing for them (1 Thessalonians 5:18; Philippians 4:6) demonstrates that we know everything comes from Him.
• We also pray because we have a real Father-child relationship with Him. Our relationship is intimate (Romans 8:15) and a way for us to abide in Him (John 15:7). Because of the work of Christ, we can approach Him as His child (Hebrews 4:16).
• Prayer glorifies God. Jesus said, “Whatever you ask in my name, this I will do, that the Father may be glorified in the Son” (John 14:13). The ultimate goal of prayer is not that we receive something but that God is glorified through His response to our prayers.
• Prayer is also God’s means of maturing us. As we pray, we learn to “not lose heart” (Luke 18:1). In it, we confess our sins (1 John 1:9) and gain spiritual strength (Ephesians 3:14–16). As we pray, we align ourselves more closely with His will (1 John 5:14) and become more like Christ.

implications for today

"Since God knows what we need, why bother praying?" That question, though common, reveals a misundertanding about the purpose of prayer. Prayer is not primarily about getting from God but about communicating with God. Our prayers are one way we develop a relationship with our Creator. During that communication, we express our needs, but getting them should not be the end goal of prayer.

Our prayers should also include confessing sin (1 John 1:9) and adoring God (Psalm 95:6).  The time you spend with your heavenly Father is your opportunity to thank Him for all He gives you every day. We can sometimes take blessings for granted until we take note of them in prayer. Additionally, at times you have something heavy on your heart, something so private and painful, you don't have anyone to share it with. You can share it with God (Psalm 62:8).

Rather than seeing prayer as an obligation before meals or getting into bed, we should view it as a time to commune with the One who knows us better than anyone else—even ourselves.