Jesus did not teach that He came to abolish the old law, in fact He told His disciples:
“Think not that I have come to abolish the law and the prophets; I have come not to abolish them but to fulfill them. For truly, I say to you, till heaven and earth pass away, not an iota, not a dot, will pass from the law until all is accomplished.” Matt. 5:17-18
He told His disciples, after His resurrection: “These are My words which I spoke to you, while I was still with you, that everything written about Me in the law of Moses and the prophets and the psalms must be fulfilled.” Luke 24:44
The sacraments were foreshadowed in the Old Testament by things that symbolized grace. When Christ came, He did not do away with those symbols, He supernaturalized them, energizing them with grace, making them more than symbols.
St. Paul also teaches: “So, then, brethren, stand firm and hold to the traditions which you were taught by us, either by word of mouth or by letter.” 2 Thessalonians 2:15
“I commend you because you remember me in everything and maintain the traditions even as I have delivered them to you.” 1 Cor. 11:2
Hope this helps!