Or what man is there among you who, if his son asks for bread, will give him a stone? Or if he asks for a fish, will he give him a serpent? If you then, being evil, know how to give good gifts to your children, how much more will your Father who is in heaven give good things to those who ask Him!
Matthew 7:9-11
Now this is the confidence that we have in Him, that if we ask anything according to His will, He hears us. And if we know that He hears us, whatever we ask, we know that we have the petitions that we have asked of Him. 1 John 5:14-15

Allow me to offer a couple of follow up thoughts regarding our good Heavenly Father only answering our prayers according to what is good.

First, when we pray for one thing and our Father answers by giving us something else, what He gives is better for us than what we asked for. That we are sometimes disappointed by His answers—that differ from our desires—only serves to remind us that we frequently do not know what is best, and therefore, sometimes, do not ask for what is best. This is when we must ask in faith, trusting that if God answers differently from our requests, He knows best.

Biblical faith is not a force to get what we want (as some false teachers insist). Rather, biblical faith trusts God especially when we do not receive what we prayed for. Biblical faith praises the Lord for not giving us what we wanted, but what He knows is best.

Second, there are times when God allows us to have what we prayed for, even though it was not what was best. Sometimes we work hard to get what we prayed for, and the Lord allows it to come to pass. He does this to school us about seeking and knowing His will before we pray, and then praying accordingly. He does this to teach us a lesson about working against His will to get what we want. When this happens, and we become aware of it, let us humbly confess our misguided prayers, repent, and ask God to sanctify our hearts and desires so that we might pray according to His will. And let us thank the Lord for teaching us—even if it is by means of sorrow.

The bottom line is that God is good, and He only always does what is best—even when we ask for what isn’t His best.