"From it did We create you, into it shall We return you, and from it shall We bring you forth another time." - Qur'an 20:55
"Say, ‘I am just a human like you..." - Qur'an 41:6
There is contradiction at all. Allah (SWT) grants everlasting life to the martyrs (2:154) and (3:169). The Prophets and Infallible Imams are much higher in degree from the martyrs, so, their continuous life is very obvious. Every Muslim salutes in his Salah, the Prophet السلام عليك أيها النبي ورحمة الله وبركاتهand all Pious servants of Allah السلام علينا وعلى عباد الله الصالحين
This means that they are alive to receive and respond to our salutations.
Allah (SWT) Has created the rules of this universe, but, His will is above all te rules. He made the fire cool and peace on Ibrahim, and He made Easa able to revive dead to alive. He ordered continuous life for His most humble servants.