Question:
Why does God need us and what was His ultimate reason for creating us?

Answer:
God does not need us, for what can we give Him? Can we make Him richer than He is? What can we do to make Him more than He is? He is omnipotent, omniscient, omnipresent and omnificent (this might be included in omnipotence). There is not nor can there be any power greater to or equal to His, which is seen in part in creation (He has much more power than is seen in creation). He sees everything, everywhere, at any given moment. He is everywhere present all the time. (Did I miss anything?)  No, He does not need us, but we surely do need Him.

Because of His love for the Son, and for us who are in Christ, He has a great plan in the ages to come for Christ and His redeemed ones: “According to the eternal purpose which He purposed in Christ Jesus our Lord (Ephesians 3:11). Read the rest of the verses in this chapter which ends with God’s ultimate reason in verse 21: “Unto Him be glory in the Church by Christ Jesus throughout all ages, world without end. Amen.” I take it that this verse is telling us that there will be glory to God in the Church by Christ Jesus for all eternity. All the members of His body, the Church, will have their part in that eternal glory which is God’s. What great love our God has for us that we should be part of and share in this glory for all eternity! See also chapter 2:7: “That in the ages to come He might show the exceeding riches of His grace in His kindness toward us through Christ Jesus.”

Dear fellow believer, whenever you get a bit discouraged, think on things like these!