God sees, hears and knows everything—including our prayers. Nothing escapes his attention. Why then did God say he would not listen to the people’s cries for help? There are several possible reasons.
In this case, God did not respond because judgment was unavoidable. Judah had disobeyed God’s laws and ignored his pleas for so long that judgment was, in effect, already on the way. Their cries were too little, too late. God even told Jeremiah not to pray for the people (see Isa 14:11–12)—that not even Moses and Samuel could have persuaded him to offer further compassion to them (see Isa 15:1).
It’s also possible that people sometimes sabotage their own prayers. The Bible mentions several attitudes and actions that can short-circuit our prayers: sin (see Ps 66:18; Isa 59:2; Jer 14:10–12), disobedience (see Pr 28:9), hypocrisy and insincerity (see Isa 29:13; Mal 1:7–9), wrong motives (see Mt 6:5–6; Lk 18:11–14; Jas 4:3), lack of faith (Heb 11:6; Jas 1:6) and even marital problems (see 1Pe 3:7).
Finally, what sometimes appears to be no answer to prayer may actually be a delayed answer (see Da 10:12–13). Other times God may deny our request in order to give us something better than what we knew to ask for.