The Jews thought of works as the means of salvation; Jesus corrects that (Joh 6:28-29). The work of God is faith, but also faith is the evidence of His work in us. The crowd was still thinking of the feeding of five thousand (Joh 6:30-34). Jesus straightens their application of manna. e.g. Moses gave it to the Jews (Joh 6:35-40). (1) Manna is a type of Christ; (2) it was a supernatural provision of Grace; (3) The manna had to be gathered daily; (4) Manna met the need according to their hunger; (5) It was profitable only as they acted in obedience. Testing was for their benefit (Deu 8:16). Israel did not learn a thing; testing God is failure to trust Him (Exo 17:1-7). In Exodus 16, Manna is a picture of Jesus incarnation. In Exodus 17, water from the rock is a picture of the Crucifixion. In Numbers 20, Moses is told to speak to the rock -- a picture of Christ resurrected. The water of the rock -- Christ is the source of never-ending blessings. (1) trials are designed to bring them/us to the end of themselves/ourselves to the cross -- a picture of general Grace (Rom 2:4, Act 17:27, Gal 4:3). When we come to the cross we find rest. When God guides us to the finished work of Christ, He guides us to rest (Mat 11:28, Heb 4:3). This is the foundation of the faith-rest life -- a journey of stages the Lord directs us to rest in trial. "Learn from Me, and you'll find rest for your souls" (Mat 11:29, Heb 4:9, Heb 4:11). Faith-rest is in stages of spiritual growth -- "faith to faith" (Rom 1:17); "strength to strength" (Psa 84:7); "glory to glory" (2Co 3:18, 1Pe 1:7). We start at the cross, are led into spirituality, then sanctification (Rom 12:1-2) and spiritual growth (2Pe 3:18), then service. It's impossible to learn without testing -- no water (Exo 17:2-3). Moses took his problems to God. You cannot learn faith-rest in conditions of comfort. Faithfulness of God in the past provides a promise to rely on in testing (Exo 16:23). Testing produces growth (Rom 5:3, Jam 1:2-5, 1Pe 1:6-7). The children of Israel tested God for 40 years; they saw His works but not His blessings (Heb 3:8-9). Heart of unbelief is evil and departed from God (Heb 3:12, Psa 106:14-15). Christ is the rock (Deu 32:15, Mat 16:18, 1Pe 2:4-8, 1Co 10:4); the water is the Holy Spirit (Joh 7:37-39). The Lord is our banner (Exo 17:8-16 Psa 60:4); He provides the victory (Gal 5:17, Rom 8:14).
After 40 years in the Egyptian palace then 40 years in the desert then 40 years leading Israel to their land Moses' life can actually teach us about living in the time we live.