It was 120 years from the time God determined to send the flood to when it began (Gen 6:3).
It was 400 years between Joseph ruling in Egypt and Israel’s deliverance (Gen 15:13).
It was about 400 years between when God spoke to Malachi and when John the Baptist proclaimed the Kingdom was at hand (Tradition).
Now a few more “statistics”: Jesus was in the wilderness 40 days/nights then Paul was in the desert for 3 years. On a more contemporary note, I know a lady who prayed for her husband’s salvation for 50 years before God answered her prayer! Consider…
“The Lord is not slow to fulfill his promise as some count slowness, but is patient toward you…” (2 Peter 3:9)
“What I am doing you do not understand now, but afterward you will understand.” (John 13:7)
To us, God seems to be slow. But then again… we’re not God are we?