Is there any biblical evidence that [asking dead saints for intercession] was a common practice in the early church?

The New Testament contains neither any example of nor any reference to this practice. Even prayers to Jesus didn't start until after the risen Jesus had revealed himself to his disciples, so those praying to him did not believe him to be dead.

Generally speaking, one cannot prove a negative, but in this case you can read the entire NT to verify. Or you can accept Martin Luther's comments about the practice, in the Smalcald Articles:

The invocation of saints is also one of the abuses of Antichrist conflicting with the chief article, and destroys the knowledge of Christ. Neither is it commanded nor counseled, nor has it any example [or testimony] in Scripture, and even though it were a precious thing, as it is not [while, on the contrary, it is a most harmful thing], in Christ we have everything a thousandfold better [and surer, so that we are not in need of calling upon the saints].

(emphasis added, but square brackets are from the original).

Luther continues a bit more from there, and it's worth the read, but the bit quoted above is the part that responds directly to the question at hand.

Naturally, although I don't think conscientious Catholics will dispute Luther's claim that "Neither is it commanded nor counseled, nor has it any example [or testimony] in Scripture," they will, I expect, vigorously dispute his scathing criticism of the practice. This is among the major divisions between protestants and Catholics.

Is there any biblical evidence that [asking dead saints for intercession] was a common practice in the early church?

The New Testament contains neither any example of nor any reference to this practice. Even prayers to Jesus didn't start until after the risen Jesus had revealed himself to his disciples, so those praying to him did not believe him to be dead.

Generally speaking, one cannot prove a negative, but in this case you can read the entire NT to verify. Or you can accept Martin Luther's comments about the practice, in the Smalcald Articles:

The invocation of saints is also one of the abuses of Antichrist conflicting with the chief article, and destroys the knowledge of Christ. Neither is it commanded nor counseled, nor has it any example [or testimony] in Scripture, and even though it were a precious thing, as it is not [while, on the contrary, it is a most harmful thing], in Christ we have everything a thousandfold better [and surer, so that we are not in need of calling upon the saints].

(emphasis added, but square brackets are from the original).

Luther continues a bit more from there, and it's worth the read, but the bit quoted above is the part that responds directly to the question at hand.

I don't think any conscientious Christian will dispute Luther's claim that "Neither is it commanded nor counseled, nor has it any example [or testimony] in Scripture," but some will, I am sure, vigorously dispute his scathing criticism of the practice. This was among the key issues in the schism between the Catholic church and what we now call protestant churches.

Is there any biblical evidence that [asking dead saints for intercession] was a common practice in the early church?

The New Testament contains neither any example of nor any reference to this practice. Even prayers to Jesus didn't start until after the risen Jesus had revealed himself to his disciples, so those praying to him did not believe him to be dead.

Generally speaking, one cannot prove a negative, but in this case you can read the entire NT to verify. Or you can accept Martin Luther's comments about the practice, in the Smalcald Articles:

The invocation of saints is also one of the abuses of Antichrist conflicting with the chief article, and destroys the knowledge of Christ. Neither is it commanded nor counseled, nor has it any example [or testimony] in Scripture, and even though it were a precious thing, as it is not [while, on the contrary, it is a most harmful thing], in Christ we have everything a thousandfold better [and surer, so that we are not in need of calling upon the saints].

(square brackets are from the original).

Luther continues a bit more from there, and it's worth the read, but the bit quoted above is the part that responds directly to the question at hand.

Naturally, although I don't think conscientious Catholics will dispute Luther's claim that "Neither is it commanded nor counseled, nor has it any example [or testimony] in Scripture," they will, I expect, vigorously dispute his scathing criticism of the practice. This is among the major divisions between protestants and Catholics.

Is there any biblical evidence that [asking dead saints for intercession] was a common practice in the early church?

The New Testament contains neither any example of nor any reference to this practice. Even prayers to Jesus didn't start until after the risen Jesus had revealed himself to his disciples, so those praying to him did not believe him to be dead.

Generally speaking, one cannot prove a negative, but in this case you can read the entire NT to verify. Or you can accept Martin Luther's comments about the practice, in the Smalcald Articles:

The invocation of saints is also one of the abuses of Antichrist conflicting with the chief article, and destroys the knowledge of Christ. Neither is it commanded nor counseled, nor has it any example [or testimony] in Scripture, and even though it were a precious thing, as it is not [while, on the contrary, it is a most harmful thing], in Christ we have everything a thousandfold better [and surer, so that we are not in need of calling upon the saints].

(emphasis added, but square brackets are from the original).

Luther continues a bit more from there, and it's worth the read, but the bit quoted above is the part that responds directly to the question at hand.

Naturally, although I don't think conscientious Catholics will dispute Luther's claim that "Neither is it commanded nor counseled, nor has it any example [or testimony] in Scripture," they will, I expect, vigorously dispute his scathing criticism of the practice. This is among the major divisions between protestants and Catholics.