Today miracles are not performed anymore because the New Covenant is written for us. It is the only proof that God has given to men under heaven to believe--by FAITH. Everything that you see today on the TV from some Pentecostal movements and the like declaring miracles still performed are all but a scam motivated by self gratification and greed of money.
1 Corinthians 13 tells us a fact that all gifts, specifically stated the prophecy and speaking of tongues, would cease and to be replaced with the permanent words inspired by God-- the New Covenant. "But when the time of perfection (full understanding) comes, these partial things will become useless" (verse 10). The New Covenant is the "time of perfection", the time of "full understanding", because it is complete and does not need any back up to prove it. Miracles are also part of the "partial things" because they serve only as proofs that what the apostles' message was true. Thus, there is no more need for any testifying miracles to prove the Good News because we already have the complete and perfect proof written for us. The New Covenant replaced the temporary miracles that were given during the apostles time, and at the end of their lives, the gift of miracles ceased. And now three things remain-- hope, faith, and love. And the one that will last forever is LOVE when we will be in heaven. Faith and hope is temporarily for the believers to have while living on earth. In heaven, there is only LOVE for eternity. There will be no more waiting (hope) and no more believing by heart (faith) because we will see Him face to face and share His glory for eternity. Amen!