How God uses symbolic acts and signs to describe what is in His Heart, showing what He is about to do or in the future to fulfil His Word.
The Lord used a rainbow as a sign of the covenant He was making with Noah and his descendants. (A powerful sign and symbol indeed and which we still witness today!)
The Lord used a Wind or instructed Angels that has been described like a Marching in the top of the mulberry trees creating a Sound, this was the signal for David and his army to attack the enemy!
Jesus uses what happened to Jonah as a sign (sometimes described as a typological metaphor) of what was to happen to Himself. Notice the warning given by Jesus not to seek or chase after signs(!) but our focus is to. be on Jesus Himself. Howbeit, God sometimes uses signs and instructs His People to obey His Word.
In this chapter we see a devout man praying and an Angel appearing in a vision, instructing him to send for Peter – the next day Peter himself falls into a trance before the visitors arrive and sees heaven open, a sign in the vision is given which helps Peter to understand what is about to happen.
Other signs and symbolic acts are found throughout scripture, but the four above helps us to understand that our God is a God of signs and wonders!