What God is showing us here is we have all we need in Him. In the span of time between day 3 and day 4, however long it might have been, He sustained the vegetation. Likewise, God wants us to know that He will sustain us too in the waiting, the wondering, and the wandering. He wants us to learn to rely on Him and not look to the tangible to sustain us.  Hebrews 10:23 says.  Let us hold fast the confession of our hope without wavering, for He who promised is faithful.

He wants our hope to rest in Him; otherwise, we build our faith on things and not on Him. The tangible does not last and does not hold the power to change our destinies.  Those tangible things like our money, our health, our position, our property even our perceived power may leave us but our God will not.